Despite the US and Russia sparring over Tuesday's attack on aid convoy, diplomatic efforts were set to continue at Syrian support group meet
In a last ditch effort to save the Syrian ceasefire from collapsing, US secretary of state John Kerry demanded on Wednesday that Russia and the Syrian government immediately halt warplanes over Syrian battle zones.
Kerry said it was the last chance to find a way "out of the carnage".
"I call on every country to cease providing support of any kind to any party that is trying to sabotage this plan," Kerry said.
Many regions in Syria are in dire need of humanitarian and medical aid. The key areas are where Syrian government forces have been accused of targeting civilians.
"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.
The United States and Russia faced off at the UN Security Council in New York. Kerry blamed Russia for the air raids on the aid convoys in Syria on Tuesday.
He said the bombing raised "profound doubt whether Russia and the Assad regime can or will live up to" ceasefire obligations.
"I emphasise this to Russia. The United States continues to believe there is a way forward that, although rocky and difficult and uncertain, can provide the most viable path out of the carnage," Kerry said.
The Russians said a coalition drone was in the area when the aid trucks were hit.
The strikes killed 20 people and destroyed 18 trucks delivering food and other supplies in Syria.
The UN Security Council met for tense crisis talks to try to revive the truce.
"We are at a make or break moment," UN secretary-general Ban Ki-moon told the council.
He urging world powers to use their influence to help restart political talks so Syrians can "negotiate a way out of the hell in which they are trapped."
Ban told the council he was looking at "options for vigorously investigating" the attack. The United Nations said the attack on the aid convoy could amount to a war crime.
After halting aid operations in response to the convoy attack, the United Nations said it was ready to resume humanitarian deliveries.
Diplomatic efforts were set to continue in New York with a new meeting of the 23-nation International Syria Support Group (ISSG) to be held on Thursday.
The United States and Russia will chair the meeting bringing together world powers to push for a ceasefire and an eventual political resolution to the bloody five-year-old conflict.
(WION with inputs from agencies)