Rebel-held eastern Aleppo city was bombarded by airstrikes killing more than 11 people, a monitoring group said Thursday, despite US Secretary of State John Kerry calling for warplanes to be grounded to give a ceasefire effort "credibility."
Rebel-held eastern Aleppo has been cut off from humanitarian assistance since July. The UN renewed its appeal to the Syrian government to let assistance in, but 40 trucks remain stuck at the Turkish border.
However, for the first time since a lethal attack on a UN aid convoy this week, trucks filled with food and medicine were again rolling inside Syria, heading towards a hard-to-reach area in rural Damascus.
More aid deliveries could go ahead in the coming days if the mission succeeds.
Tensions between the United States and Russia, the main backer of President Bashar al-Assad, have spiked following the Monday attack on the aid convoy, which killed 21 people and forced a temporary halt to humanitarian deliveries. The US blames Russia but Moscow denies responsibility.
Activists say Syrian or Russian warplanes dropped incendiary bombs on eastern Aleppo as part of more than 200 missiles that landed in the area overnight.
"The whole city was on fire during the night," said Ibrahim al Hajj, a spokesman for the White Helmets rescue group, which operates in rebel-held areas of Syria.
"Please, President Assad, do your bit to enable us to get to eastern Aleppo and the other besieged areas," Jan Egeland, a senior UN advisor on humanitarian efforts in Syria, pleaded from Geneva.
Egeland added that the rebels had yet to give their approval for aid to be delivered to eastern Aleppo.
A ceasefire brokered by the US and Russia collapsed on Monday, after largely holding for a week, when Syrian planes began attacks on rebel-held areas.
Kerry is still keen to reinstate the ceasefire, despite pessimism voiced by top Russian officials, but has demanded Moscow and Damascus abide by the terms.
"I believe that to restore credibility to the process, we must move forward to try to immediately ground all aircraft flying in those key areas in order to de-escalate the situation and give a chance for humanitarian assistance to flow unimpeded," Kerry said on Wednesday.
"And if that happens, there is a chance of giving credibility back to this process."
The UN says it plans to try to restart more wider-reaching peace talks in the coming weeks, though previous efforts have barely got off the ground.
UN Secretary-General Ban Ki-moon this week was sharply critical of al-Assad's government, which regularly denies any wrongdoing.
"Many groups have killed innocent civilians — none more so than the government of Syria, which continues to barrel bomb neighborhoods and systematically torture thousands of detainees," said Ban.
Meanwhile, some 350 rebel fighters and their families began to evacuate al-Waer, a hard-hit area of Homs city, in the centre of the country, under a deal reached between rebel groups and the Syrian government.
The movements were taking place under the close watch of the Syrian army, which had placed a siege on the neighbourhood, a key factor in the rebels agreeing to give up their last district in Homs in stages.
Part of the deal stipulates the district, where tens of thousands of people still live, will get aid. Some rebel factions in other parts of the country have been critical of the fighters in al-Waer agreeing to a deal, despite the desperate situation.
Veiled women and bearded men, along with children, were seen carrying their bags and leaving in green buses escorted by the Syrian Red Crescent. The deal stipulates the fighters will move to northern areas of the country under rebel control and can take light weapons.
The Syrian government claims only hardline Islamic armed groups are in al-Waer.