SOHR says at least 34 people killed and tens more injured in an explosion in the city of Idlib. Earlier, regime forces recaptured a strategically important town in the province of Idlib in the latest advance into opposition-held territory.
At least 34 people were killed and tens more injured, including civilians, in an explosion in Syria's northwestern city of Idlib, a war monitor reported on Sunday.
The Syrian Observatory for Human Rights (SOHR) said the explosion targeted the headquarters of a minor rebel faction in Idlib. It was not immediately clear what the nature of the attack was. According to some reports, the explosion was caused by a car bomb or vehicle-bourne bomb.
TRT World's Sarah Firth says the latest attack could be the result of infighting between rebels.
Ambulances and rescue teams rushed to the explosion site. Efforts were under way to pull out the bodies and rescue the injured trapped under the rubble of the targeted building and neighbouring houses, the monitor added.
Idlib province is a stronghold of rebels in Syria and is situated on the border with Turkey, one of the main backers of the opposition against regime leader Bashar al-Assad.
The Syrian army and its allies launched an offensive in October to recapture the provinces of Idlib and Hama, and it has since been making swift advances.
The main rebel force in Idlib is Tahrir al-Sham, spearheaded by the former al Qaeda affiliate in Syria previously called Nusra Front.
The Syrian army lost Idlib to insurgents when the provincial capital fell in 2015. It became the only province fully under opposition control.
Syrian television says regime forces recaptured a strategically important town in the northwestern province of Idlib in its latest advance into rebel-held territory this year. The state-affiliated Al Ikhbariya TV says Sinjar was taken on Sunday.
The Britain-based Syrian Observatory (SOHR) for Human Rights monitoring group says the gain "opens the road" for the government troops to march on the rebel-held Abu al Duhur air base about 19 kilometres, or 12 miles, to the north.
Syrian regime forces and allied militiamen have been advancing on Idlib, the largest remaining rebel-held territory in the country's north, forcing thousands of civilians to flee toward the border with Turkey in freezing winter temperatures.
The offensive on Idlib — a large border province in northwestern Syria packed with civilians and dominated by al Qaida-linked militants — was expected after the defeat of the Daesh group late last year. Last week, Russia's Foreign Minister Sergey Lavrov said the main military operations against Daesh in Syria have ended and signalled that the focus would shift to Daesh-linked militants.
Regime leader Bashar al Assad's forces have since October taken back territory in Idlib and the northeastern province of Hama.
A pro-Damascus media unit and a war monitor said the Syrian army and forces allied with the regime captured a town and several villages near Idlib as they approached Abu al Duhur, a military airport, which opposition factions captured from Assad’s troops in September 2015.
The Syrian army and its allies "have gained control over the town of Sinjar," 14 kilometres (nine miles) from Abu al Duhur, and three villages to the west, the media unit run by Assad-ally Hezbollah reported.
SOHR, which monitors the fighting through a network of activists, said on Sunday the army had taken more than 95 villages in Hama and Idlib since October 22, including around 60 in Idlib alone during the past 14 days.
"Battles have shifted now to the northwest of Sinjar after the Syrian army and its allies have controlled the town," the Britain-based monitor reported earlier.
The main rebel force in Idlib is Tahrir al Sham, spearheaded by the former al Qaeda's affiliate in Syria previously called Nusra Front.
Risks of Idlib operation
The Idlib offensive carries significant risks.
The province bordering Turkey is home to an estimated two million Syrians, including tens of thousands of people who fled fighting elsewhere.
A full-blown government offensive could cause large-scale destruction and massive displacement.
Turkey, a supporter of the opposition, has deployed military observers in the province as part of a de-escalation deal with Iran and Russia, but that has not stopped the fighting on the ground or Russian airstrikes against the insurgents.
It is not clear how far the current offensive aims to reach, and recapturing the entire province is expected to be a long and bloody process.
Opposition activists say the main target for the regime for now appears to be the sprawling air base of Abu al Duhur, on the southeastern edge of the province and securing the Damascus-Aleppo road that cuts through Idlib province.
Enter the ‘Tiger’
The offensive gained more intensity on Christmas Day, when one of Assad's most trusted and experienced officers took command of the operation to extend the regime’s presence toward Idlib and boost security for the road that links the capital, Damascus, with Aleppo, Syria's largest city.
Brigadier General Suheil al Hassan, also known among his troops as "Tiger," has led elite forces to many victories against insurgents since the conflict began nearly seven years ago. He has been credited most recently with the defeat of Daesh in much of eastern Syria, including the months-long battle for the city of Deir Ezzor.
"Conditions on the ground are wretched for the rebels," said an opposition activist based in northern Syria who asked to be identified by his first name, Hassan, for fear of reprisals by insurgents. He said rebels are stuck in a two-front battle with government forces and remaining pockets of Daesh militants. He said the Russian airstrikes have exacted a heavy toll.
Another opposition activist based in Hama province, Mohammed al Ali, said the Russians and the Syrian government are "carpet bombing" villages before pushing into them.
"The Russian airstrikes, weak fortifications and Daesh attacks in Hama" have all helped government forces, he said by telephone.
Hassan and Ali said it is highly unlikely that government forces would march toward the provincial capital, also named Idlib, because it would set up a costly battle with highly experienced and well-armed al-Qaida-linked insurgents. The province is dominated by the Levant Liberation Committee, which claims to have severed ties with al Qaida but is widely believed to still be affiliated with it.
Hassan's chief mission for now appears to be securing the Damascus-Aleppo road.
In December 2016, Assad's forces captured rebel-held parts of the city of Aleppo, marking the government's biggest victory since the conflict began. The main road to the capital remained perilous, however, with insurgents attacking it from the west and Daesh from the east. The troops have since driven Daesh back, but the western side remains exposed.
Four days after Hassan took over operational command, troops managed to break through the militants' heavy defences and capture the town of Abu Dali, a link between Hama, Idlib and Aleppo.
Last week, regime forces advanced to within around 12 kilometres (8 miles) of Khan Sheikhoun, where a sarin nerve gas attack killed more than 90 people last year, prompting the US to launch a missile attack on Assad's troops. Experts from the UN and other monitoring groups blamed the chemical attack on the government, which denied responsibility.
SOHR says that some 43 civilians, 57 militants and 46 pro-government forces have been killed since the offensive led by Hassan began on December 25.
"The regime wants to take the eastern part of Idlib province," said the Observatory's chief, Rami Abdurrahman. "Their aim is to remove any threat to the road" between Damascus and Aleppo, he said.