A meeting between Turkey's President Recep Tayyip Erdogan and Russia's President Vladimir Putin on September 17 in Sochi resulted in a decision to demilitarise the zone between regime forces and the opposition and rebels in northern Syria's Idlib.
The region is the last major opposition and rebel stronghold in Syria.
The Assad regime and its allies had been reported to be planning an all-out assault to take back Idlib, and had stepped up attacks on the region.
The ultimate goal of the expected assault was Idlib city, one of the designated de-escalation zones agreed by Turkey, Russia and Iran as part of the Astana process.
Turkey and the United Nations have led international calls for restraint.
According to the UN, the war, now in its eighth year, has already claimed the lives of over 500,000 people and has displaced over 12 million. It fears a humanitarian catastrophe in Idlib, which is home to some three million people, many of them refugees who fled the war in other parts of the country.
All times below are in GMT (Syria is GMT+3)
Monday, October 8
0830 GMT: Turkey's Anadolu Agency reports that Syrian opposition fighters in Idlib will complete the withdrawal of heavy weapons from the front line by the end of the day.
Saturday, October 6
1404 GMT: Two Turkey-backed Syrian rebel officials told Reuters that rebel groups had begun to withdraw heavy weaponry from a demilitarised zone in northwest Syria on Saturday morning.
“The process of withdrawing heavy weapons began this morning and will continue for a number of days,” one rebel official told Reuters.
Wednesday, October 2
1930 GMT: Russian President Vladimir Putin said on Wednesday that the demilitarised zone in Syria's Idlib was effective and no major military actions are planned in the region.
"I have every reason to believe that we will achieve our goals," Putin said, referring to the demilitarised zone set up by Russia and Turkey in Idlib.
"And that means, no large scale military actions are expected there," he said. "Military action for the sake of military action is unnecessary."
Monday, October 1
0800 GMT: France supports the recent Russia-Turkey agreement on installing a demilitarised zone in Syria's Idlib, the French foreign ministry said on Monday in a statement.
The statement comes a day after French Foreign Minister Jean-Yves Le Drian held talks with his Turkish counterpart Mevlut Cavusoglu in Paris.
"The talks focused mainly on the Syrian issues. Jean-Yves Le Drian expressed support for the [Russia-Turkey] agreement in Sochi on September 17 that establishes a demilitarised zone in the Idlib area and allows to avoid the offensive operation by the [Damascus] regime and its allies at this stage," read the statement.
Sunday, September 30
1315 GMT: Syrian rebels denied they had pulled any heavy arms from a major opposition bastion in Syria's Idlib.
“There have been no withdrawals of heavy weapons from any area or any front. This report is denied, completely denied,” NLF spokesman Naji Mustafa told AFP.
The Syrian Observatory for Human Rights monitor had earlier said one faction of the NLF - Failaq al Sham - began withdrawing its heavy weapons under the Turkish-Russian agreement.
0700 GMT: The Syrian Observatory for Human Rights said on Sunday that rebel group Failaq al Sham has started withdrawing its forces and heavy arms from a demilitarised zone in northwest Syria.
The group is the first to comply with a requirement to leave a demilitarised buffer zone set up by Turkey and Russia to avert a Russian-backed Syrian army offensive, Rami Abdulrahman, head of the UK-based war monitor told Reuters news agency.
Rebel sources could not immediately be reached for comment.
Thursday, September 27
1028 GMT: Syrian opposition said on Thursday they have growing confidence that their militant rivals will comply with a requirement to leave a demilitarised buffer zone in Idlib province set up by Turkey and Russia to avert a Russian-backed Syrian regime offensive.
The position of the biggest militant group, Hayat Tahrir al Sham, spearheaded by al Qaeda's former Syrian offshoot, will be crucial to the deal's success, but it has so far said nothing.
Wednesday, September 26
1400 GMT: US President Donald Trump hailed Turkey for helping to avoid offensive on Syria's Idlib, during his speech at the UN Security Council.
He also thanked Iran, Russia and Syrian regime for slowing down attack on Idlib, saying "get the terrorists, but I hope the restraint continues, the world is watching."
0500 GMT: Turkey's President Recep Tayyip Erdogan in an exclusive interview told Reuters it was impossible for Syrian peace efforts to continue with Syrian regime Bashar al Assad in power, adding the withdrawal of "radical groups" from Idlib had already started.
"This part of Syria will be free of weapons which is the expectation of the people of Idlib ... who welcomed this step," he said.
Monday, September 24
0000 GMT: Turkish President Recep Tayyip Erdogan said on Sunday that Turkey would continue to increase the number of safe zones within Syria to include the east of the Euphrates River.
In his address to Turkish and Muslim communities in New York, organised by Turkish American National Steering Committee, Erdogan said Turkey’s struggle will continue until the terror threat against it ends and it would eradicate terror gangs that aim at Syria’s future.
Sunday, September 23
15:40 GMT: Two insurgent groups rejected a deal reached this month between Russia and Turkey to establish a demilitarised zone in Syria's Idlib region with one saying on Sunday that the agreement aims to "bury the revolution."
Huras al Din, Arabic for Guardians of Religion, called the deal to establish the zone a "great conspiracy."
The group is made up mostly of al-Qaida fighters that broke away from Hayat Tahrir al Sham in Idlib.
The Ansar al Din Front, issued a statement Sunday carried by Syrian rebel and opposition social media pages, calling on all insurgent groups in Idlib "during this critical period to overcome their differences because of the existential battle since our enemy does not differentiate between us."
Friday, September 21
15:00 GMT: A trilateral meeting on Syria will be held in New York with the foreign ministers of Turkey, Russia, and Iran, Turkey's foreign minister Mevlut Cavusoglu said.
In the wake of the Sochi agreement, the "ceasefire must be fully established and focus should be on political solution," Cavusoglu said.
19:05 GMT: Turkish-backed Free Syrian Army fighters said they would cooperate with Turkish diplomatic efforts that halted a Russian-backed regime offensive in Idlib, but they will not surrender their weapons or territory.
Thursday, September 20
06:05 GMT: Jan Egeland, the top UN humanitarian aid official for Syria, says he sees "great potential for a lot of fighting" in opposition and rebel-held Idlib province despite an accord between Russia and Turkey that has delayed a military offensive.
Wednesday, September 19
18:30 GMT: The US Department of State has omitted the PYD/YPG terrorist group from its 2017 Country Reports on Terrorism.
The previous edition of the report noted that Turkey views the Syria-based PYD/YPG as an extension of the PKK militant group, which the US, Turkey and the EU list as a terrorist organisation.
Tuesday, September 18
11:00 GMT: The UN’s humanitarian coordinator for the Syria crisis has welcomed the Turkey, Russia agreement to demilitarise Idlib province.
Speaking to Anadolu Agency in Ankara, Panos Moumtzis said it is “very important” to avoid military escalation, protect civilians, respect freedoms, and make sure humanitarian work and access is allowed in Syria."
“The Sochi agreement is extremely important and definitely a step in the right direction,” he added.
Monday, September 17
16:20 GMT: The leaders of Turkey and Russia have agreed to create a “demilitarised zone” around Syria’s rebel-held province of Idlib, President Vladimir Putin said on Monday after lengthy talks with his Turkish counterpart Recep Tayyip Erdogan.
“We have decided to create a demilitarised zone some 15 to 20 kilometres deep along the line of contact between the armed opposition and regime troops by October 15 of this year,” he said.
05:30 GMT: Syrian opposition and rebels have dug trenches around towns, reinforced caves for cover and put up sandbags around their positions. They issued calls to arms, urging young men to join in the defence of Idlib.
This time, it's "surrender or die."
Sunday, September 16
23:00 GMT: Syrians in Idlib are heading underground as they brace themselves for a Russian-backed regime offensive on the country's largest remaining rebel-held zone.
Friday, September 14
1548 GMT: Turkish presidential spokesman Ibrahim Kalin says it is too early to talk about a humanitarian corridor for Idlib.
After a meeting with French, German and Russian officials in Istanbul, Kalin said that they have reached a consensus that the result of an attack on Idlib would be severe.
1355 GMT: Russian Foreign Minister Sergey Lavrov said on Friday that the Syrian regime is not preparing a major offensive against the opposition-held Idlib, adding that Moscow will do everything to protect civilians.
“What is being presented at the moment as the beginning of a Russian-backed offensive by Syrian forces is not a faithful representation of the facts,” said Lavrov during a German-Russian forum in Berlin.
0215 GMT: Turkey’s foreign minister says Washington should reconsider its alliances in Syria.
Writing in the The New York Times, Mevlut Cavusoglu warned that the YPG terrorist group, which the US backs in Syria, has struck an alliance with Bashar al Assad and is sending troops to help him recapture Idlib.
Thursday, September 13
1145 GMT: UN Resident & Humanitarian Coordinator in Syria Ali al Za'tari: "Our teams are working 24/7 on stockpiling aid for up to 900,000 Idlib civilians who might flee."
1115 GMT: UN humanitarian coordinator for Syria says he has shared the GPS coordinates of Idlib health facilities and schools with Russian and US officials.
Turkey sent military reinforcements to strengthen its observation posts in Idlib, activists reported.
The Turkish deployment came amid a lull in a concerted regime and Russian aerial bombing campaign on the southern edge of Idlib.
The Britain-based Syrian Observatory for Human Rights said a Turkish convoy entered from Kfar Lusin crossing in northern Idlib, heading to some of the 12 Turkish observations points that ring Idlib.
Wednesday, September 12
1000 GMT: Any military operation in Syria’s Idlib would drag a region rife with problems to disaster, Turkey’s Defence Minister Hulusi Akar said.
Speaking at a meeting of ambassadors, Akar said Ankara is still working with Russia and Iran to try to prevent a humanitarian tragedy in the case of a threatened Syrian regime offensive.
“Idlib is on the brink of a new crisis. Turkey is working with Russia, Iran and other allies to establish peace and stability in Syria and to stop the humanitarian tragedy,” Akar said.
Tuesday, September 11
1955 GMT: UN Secretary-General Antonio Guterres warned Syria and its backers against launching a full-scale battle in Idlib, saying the province "must not be transformed into a bloodbath."
Guterres told reporters at UN headquarters that an all-out assault "would unleash a humanitarian nightmare unlike any seen in the blood-soaked Syrian conflict."
1840 GMT: Iran's UN ambassador is warning the US, Britain and France against using force against Syria "under the pretext" of its alleged use of chemical weapons.
Gholamali Khoshroo told the UN Security Council that Syria's declared chemical weapons have been destroyed and this would only be "a fabrication to use force" and "further complicate the situation."
1840 GMT: US Defense Secretary Jim Mattis stressed that Syrian regime leader Bashar al Assad has been well warned against any chemical weapons use in an anticipated assault on Idlib province.
1828 GMT: Russia hopes for a peaceful resolution of the situation in Syria's Idlib but believes it is up to Turkey to separate militants from the moderate opposition, Russia's Syria envoy Alexander Lavrentiev said.
1825 GMT: Turkey's UN envoy demanded an "immediate and complete" cease-fire to halt all military operations in northwestern Syria's Idlib province.
"We invite the international community to vocally and actively support our efforts to this end," Feridun Sinirlioglu told the Security Council during a session on the province.
1755 GMT: US Ambassador Nikki Haley accused Assad and his allies Russia and Iran of "demolishing" the last major opposition and rebel-held stronghold in Idlib and asking Western opponents "to call it peace" and fund reconstruction efforts in the country.
1703 GMT: French Foreign Minister Jean-Yves Le Drian warned that a Syrian regime offensive on Idlib could scatter thousands of foreign militants abroad, posing a security threat to the West.
"There are in all likelihood dozens of French fighters from both Al Qaeda and Daesh" in Idlib, Le Drian told France's BFMTV, warning that there were "also many terrorists from other nations who could scatter" in the event of a joint Syrian-Russian offensive, posing "risks for our security.
1431 GMT: Russia claimed that Syrian rebels had begun working on film footage that would be presented to the world as the aftermath of an alleged chemical attack by the Syrian regime forces.
1040: Turkish President Recep Tayyip Erdogan called on Russia and Iran to halt a looming "humanitarian disaster" in Idlib, saying Syrians there could not be left to the mercy of Assad.
Writing in the Wall Street Journal, Erdogan said the West had an "obligation to stop the next bloodshed" but that regime allies Moscow and Tehran were "likewise responsible for stopping this humanitarian disaster".
Monday, September 10
1710 GMT: Air and ground attacks on Syria's Idlib must stop and a ceasefire must be established in the area, Turkish Defence Minister Hulusi Akar was reported as saying by broadcaster NTV.
1326 GMT: "As of 9 Sept. 30,542 people have been displaced from northwest Syria, moving to different areas across Idlib," David Swanson, spokesman for the UN Office for the Coordination of Humanitarian Affairs (UNOCHA) said.
1224 GMT: The UN's humanitarian chief warned that a large-scale military operation against Idlib could create "the worst humanitarian catastrophe" of this century.
"There needs to be ways of dealing with this problem that don't turn the next few months in Idlib into the worst humanitarian catastrophe with the biggest loss of life in the 21st century," Mark Lowcock told reporters in Geneva.
Sunday, September 9
1539 GMT: Regime and Russian aircraft pounded Idlib with missiles and barrel bombs, killing at least two children, a monitor said.
"Regime helicopters dropped more than 60 barrel bombs on the village of Hobait in Idlib's southern countryside," said Rami Abdel Rahman, a head of the Syrian Observatory for Human Rights (SOHR). The raids killed at least two children and wounded six other people, he said.
In the neighbouring province of Hama, Russian jets carried out more than 10 strikes on rebel positions in the village of Al Latamneh, he said.
Saturday, September 8
1521 GMT: Idlib was targeted by the "most violent" Russian air strikes in a month, the SOHR said.
At least four civilians including two children were killed in the strikes and as dozens of barrel bombs were dropped by regime aircraft, the Britain-based monitor said.
1250 GMT: Russia said it had "irrefutable information" Syrian rebels were planning an imminent "provocation" in Idlib province to justify Western intervention.
Friday, September 7
2015 GMT: Russian air strikes killed five people in Syria's Idlib, the SOHR said.
Later in the day, shelling by militants killed 10 civilians in a neighbouring province, it said.
1300 GMT: A trilateral summit of the presidents of Iran, Turkey and Russia in Tehran agrees to continue to work together to resolve the Syrian issue, but does not agree a joint mechanism moving forward on Idlib. The UN has warned that a regime assault on Idlib could be a humanitarian catastrophe.
1200 GMT: Air strikes hit parts of Idlib province, the war monitor said, as the presidents of Iran, Russia and Turkey met in Tehran to discuss the fate of the last opposition and rebel stronghold in Syria. The SOHR said the strikes were targeting positions belonging to militant groups in the northern Hama and southern Idlib provinces.
Thursday, September 6
2100 GMT: The US says there is "lots of evidence" that chemical weapons are being prepared by Syrian regime forces in Idlib. "I am very sure that we have very, very good grounds to be making these warnings," said Jim Jeffrey, US Secretary of State Mike Pompeo's special adviser on Syria.
"Any offensive is to us objectionable as a reckless escalation," Jeffrey said. The White House has warned that the United States and its allies would respond "swiftly and vigorously" if regime forces used chemical weapons in the widely expected offensive.
Tuesday, September 4
0908 GMT: A Syrian rebel and a war monitor said Russian air strikes had resumed against militants in Syria's northwestern Idlib province after several weeks.
Sunday, September 2
1320 GMT: France's foreign minister Jean-Yves Le Drian says Syrian regime leader has won his country's civil war but won't "win the peace" without a political solution brokered by the international community.
1122 GMT: Pope Francis appealed to all parties who have influence in Syria to defend human rights and safeguard the civilian population in Idlib.
Saturday, September 1
1853 GMT: Near the city of Jisr al Shughur, "a pregnant woman and her daughter were killed by these regime strikes," the SOHR said, reporting similar artillery fire in other rebel-held areas.
Friday, August 31
1427 GMT: Turkey has designated Tahrir al Sham as a terrorist organisation, according to a presidential decision published on Friday.
1348 GMT: Russian Foreign Minister Sergei Lavrov said the Syrian regime had every right to chase militants out of Idlib and that talks on establishing humanitarian corridors there were ongoing.
1300 GMT: EU Foreign Policy Chief Federica Mogherini said ministers were sending out a strong message on Idlib, stressing the need to prevent and avoid a military action that would be a "humanitarian catastrophe."
1259 GMT: Turkey is very much concerned over a possible attack on Idlib, Foreign Minister Mevlut Cavusoglu said.
Speaking to reporters ahead of a meeting of EU and candidate countries' foreign ministers, Cavusoglu said: "Turkey is trying to prevent an attack on Syria's Idlib, which would be a disaster."
1210 GMT: “A large-scale military operation of the Syrian regime in and around Idlib would spark another humanitarian catastrophe with potentially hundreds of thousands of people seeking shelter near Turkey’s border,” German government's deputy spokeswoman Ulrike Demmer said.
1120 GMT : Opposition fighters have blown up two bridges linking areas they control to regime-held territories in northwestern Syria in anticipation of a military offensive, said the SOHR.
The bridges linked rebel and regime-held villages in al Ghab plains, south of Idlib.
Thursday, August 30
1952 GMT: The UN envoy for Syria Staffan de Mistura proposed that civilians holed up in Idlib could evacuate to regime areas, a move that would send many back into parts of Syria they once fled.
1828 GMT: Turkey is in talks with Russia and Iran to prevent an Aleppo-like disaster in Syria's Idlib, Turkey's President Erdogan said.