US officials later confirmed they believe two Russian SU-24 bomber aircraft were in the skies above the convoy and that the US believed Russia was responsible for the attack.

Russian and regime forces have also resumed their bombardment of the rebel-held eastern half of Aleppo, with dozens of airstrikes pummelling the city.

“It is unbelievable the number of airstrikes that are targeting Aleppo neighbourhoods”, said Abdelkafe al-Hamdo, an opposition activist in the city.

Western diplomats said they were urgently trying to revive the ceasefire agreement with Russia, which they see as the only real path to slowing the violence in Syria and trying to restart political negotiations to be bring the five-year war to an end.

The chances for a renewed deal appeared slim after a furious exchanges between the US and Russia at the Security Council on Wednesday.

Sergey Lavrov, the Russian foreign minister, ruled out a fresh ceasefire unless “all sides” agreed, saying rebel groups had used previous truces as an opportunity to rearm and that the US had failed to use its influence with militants to persuade them to respect the ceasefire.

Mr Kerry replied that his colleague was living in “a different universe” and accused Russia of deliberately obfuscating about the aid convoy bombing.