Syrian warplanes have pounded a rebel-held town near the Lebanese border, as peace talks between the government and opposition continued in Geneva.
The talks have been accompanied by a sharp rise in violence on the ground in Syria. The Britain-based Syrian Observatory for Human Rights said on Wednesday that at least 4,959 people had died in Syria in the three-week period since January 22, when the first round of talks began in Switzerland.
The group, which documents the fighting on the ground through a wide network of activists, say the period has seen the highest death toll since the uprising against President Bashar al-Assad started in March 2011.
The Observatory reported at least 10 air strikes on Yabroud, the last rebel stronghold in Syria's mountainous Qalamoun region, on Wednesday. Backed by Lebanese Hezbollah fighters, the Syrian army has been on a crushing offensive there since early December.
Officials in Arsal, on the Lebanese side of the border, said more than 300 Syrians had crossed the border to escape violence.
Meanwhile, in the central city of Homs, more than 200 civilians were evacuated from besieged rebel-held districts, governor Talal al-Barazi said.
"The operation went well and smoothly," Barazi told the AFP news agency.
A ceasefire in the city was due to expire at midnight on Wednesday. Food aid has been delivered and hundreds of civilians evacuated since Friday, when the UN-brokered humanitarian truce went into effect.
In Geneva, the opposition urged Russia, a key ally of Assad, to take a more forceful stand with the Syrian government.
Russian Deputy Minister of Foreign Affairs Gennady Gatilov met UN mediator Lakhdar Brahimi on Wednesday morning, before Brahimi brought the Syrian sides together for another session.
"I do hope that the Russians will put enough pressure on the regime delegation to be flexible,'' said Anas al-Abdeh, a member of the opposition negotiating team.
The opposition also called for a transitional governing body to be set up that would oversee a total ceasefire under UN monitoring, and be empowered to drive out foreign fighters deployed on both sides of the civil war.
The confidential paper, seen by Reuters news agency, was presented to Brahimi and the Syrian government delegation.
Syrian Deputy Foreign Minister Faisal Maqdad said the government was willing to discuss the proposal to evict foreign fighters, signalling a rare sign of accord between the warring foes.
"We are not closed to discussing any issue. But we have to discuss them one by one," he told Reuters.