At least 45 civilians, including four children killed in rebel-enclave near Damascus on Wednesday by regime air strikes, bringing the death toll in more than two weeks of bombing to 850 civilians.
Fresh air strikes on eastern Ghouta near Damascus brought the death toll for Wednesday's bombardment on the rebel-held enclave near Damascus to 45, a war monitor said.
The Syrian Observatory for Human Rights monitoring group said at least 18 of the day's victims were killed in strikes carried out by Russian warplanes on Hammuriyeh.
The head of the Britain-based Observatory, Rami Abdel Rahman, said four of the 45 victims were children. The Observatory had earlier reported 18 dead in Ghouta on Wednesday.
The latest deadly raids brought to around 850 the number of civilians killed since Syrian regime and allied forces intensified their air campaign on the besieged enclave on February 18.
The blistering onslaught has prompted outrage against the regime, with the United Nations' human rights chief saying the government was orchestrating an "apocalypse" in Syria.
Regime and it's allied militias with Russian air cover have taken more than half of the enclave and "have effectively cut the rebel-held enclave in half," said the monitor.
Earlier on Wednesday, the Syrian regime sent reinforcements to eastern Ghouta, hours before a top-level UN meeting on the escalating violence.
Heavy air strikes battered several key towns in the zone on Wednesday, as Syria's regime dispatched hundreds of militiamen to the front.
TRT World's Francis Collings has more on the story.
Erdogan and Rouhani phone call
The Turkish and Iranian leaders on Wednesday discussed recent developments in the enclave, according to Turkish presidential sources.
In a phone conversation, Turkish President Recep Tayyip Erdogan and his Iranian counterpart Hassan Rouhani stressed that their nations plus Russia must work together to make the UN’s Syria ceasefire a reality, said the sources, who asked not to be named due to restrictions on speaking to the media.
The two leaders agreed to accelerate efforts to realise the cease-fire in order to end the tragedy in eastern Ghouta and deliver humanitarian aid to civilians.
The trio - Turkey, Russia and Iran- has launched the Astana peace talks last year with the aim of putting an end to violence and improving the humanitarian situation in war-torn Syria.
"At least 700 Afghan, Palestinian, and Syrian loyalist militiamen came from Aleppo and were sent late on Tuesday to Ghouta," said Rami Abdel Rahman, head of the Syrian Observatory for Human Rights.
The Britain-based war monitor said the reinforcements were deployed to two main battlefronts on the western side of the enclave, including the town of Harasta.
Regime troops on Wednesday were within firing range of the key towns of Misraba and Beit Sawa and had taken up positions at the edges of Jisreen and Hammuriyeh.
The toll in more than two weeks of bombing reaches to around 850 civilians, including 183 children.
"Apocalypse" in Syria
The bombardment has continued despite a one-month ceasefire demanded by the United Nations Security Council more than a week ago.
The council will meet behind closed doors on Wednesday afternoon to discuss the failed truce, after France and Britain requested urgent talks.
UN human rights chief Zeid Ra'ad Al Hussein said the Syrian regime and its foreign allies were already planning their next "apocalypse."
"This month, it is eastern Ghouta which is, in the words of the Secretary General, hell on earth; next month or the month after, it will be somewhere else where people face an apocalypse – an apocalypse intended, planned and executed by individuals within the regime, apparently with the full backing of some of their foreign supporters," said Hussein.
Eastern Ghouta's roughly 400,000 residents have lived under government siege since 2013, facing severe shortages of food and medicines even before the latest offensive began.
Forty-six aid trucks entered the area on Monday for the first time since the offensive, but had to cut short their deliveries and leave due to heavy bombardment.
Nearly half of the food aid could not be delivered and Syrian regime authorities removed some medical and health supplies from the trucks, the UN said.
Secretary-General Antonio Guterres urged all warring sides to allow aid trucks to return for a planned second delivery to the enclave's main town of Duma on Thursday.
Linda Tom, spokesperson for the UN's humanitarian coordination office OCHA in Syria, said the aid would aim to reach 70,000 people in Duma and would include medical supplies not allowed in Monday's delivery.
Rebels deny talks with Russia
Inside eastern Ghouta on Wednesday, AFP correspondents heard warplanes carrying out a barrage of strikes on the battleground towns.
Residents in Duma were driving frantically through the streets to escape from bombing zones, with cars brushing by each other in close calls.
Wednesday's raids came despite a daily "humanitarian pause" announced by Russia last week that is meant to bring calm to eastern Ghouta between 0700 GMT and 1200 GMT each day.
During that pause, Moscow said, it would guarantee safe passage to civilians and rebels wishing to flee the enclave.
No Syrian civilians are known to have used the "humanitarian corridor."
The two main rebel groups in eastern Ghouta – Jaish al Islam and Faylaq al Rahman – deny that the exit routes or the pauses have been coordinated with them.
"There is no communication with the Russians, directly or indirectly," said Wael Alwan, spokesman for Faylaq al Rahman.
More than 340,000 people have been killed and millions displaced in Syria since the civil war started in 2011 with the brutal repression of anti-regime protests.