The US has said it holds Russia responsible for a deadly attack on an aid convoy near the Syrian city of Aleppo on Monday, BBC reported on Wednesday.
The White House has called it an "enormous humanitarian tragedy"
. Meanwhile, US officials have told the BBC that two Russian war planes were responsible for the attack.Russia strongly denies
involvement of its own or Syrian planes, and says the incident was caused by fire on the ground and not by an air strike."There are no craters and the exterior of the vehicles do not have the kind of damage consistent with blasts caused by bombs dropped from the air… We have nothing to do with this situation,"
a statement from the defence ministry said.
Separately, an air strike hit a medical center near Aleppo on Tuesday night local time, killing four medics working for the Union of Medical Care and Relief Organizations (UOSSM), the group said.
The attack on the rebel-held town of Khan Touman also killed at least nine rebel fighters and was carried out by either Syrian or Russian warplanes, UK-based monitoring group the Syrian Observatory for Human Rights said.
The rebels were from Jaish al-Fatah, an Islamist group not officially part of the Western-backed alliance but one that works alongside the Free Syrian Army, according to BBC.
Speaking earlier about Monday's attack on the aid convoy, US officials, speaking on condition of anonymity, said two Russian SU-24 attack aircraft were in the sky above the convoy at the precise moment it was hit in Urum al-Kubra.
The strike, they added, was too sophisticated to have been carried out by the Syrian army.
White House spokesman Ben Rhodes later said: "There only could have been two entities responsible, either the Syrian regime or the Russian government."
Eighteen of 31 lorries were destroyed and about 20 civilians
were killed including a senior official of the Syrian Arab Red Crescent.
The attack prompted the UN to suspend all aid convoys in Syria
Meanwhile, diplomats in New York were trying to save a week-old truce agreement brokered by the US and Russia which was declared over by Syrian military hours before the incident.
US Secretary of State John Kerry, speaking alongside his Russian counterpart Sergei Lavrov, insisted the cessation of hostilities deal was "not dead"
, following talks with delegates of the Syria Support Group.
They are to meet again on Friday. And the UN Security Council is due to hold a high-level meeting on Syria on Wednesday.