According to a statement from ministry spokesman Igor Konashenkov: "Russian and Syrian planes did not carry out any air attack on humanitarian aid convoys belonging to the UN in southwestern Aleppo."

Konashenkov said footage from Monday’s scene had been "meticulously" examined and concluded there was no sign of ammunition which hit the convoy.

However, upon a question from Anadolu Agency, the U.S. State Department said it would stand by previous statements which urged Moscow to fulfill its ceasefire commitments, including getting the Syrian government to permit unimpeded aid access.

The department said yesterday that Damascus and Moscow knew the convoy’s destination “and yet these aid workers were killed in their attempt to provide relief to the Syrian people,” apparently placing the blame for the attack on Russia or Syria.

On Monday, a convoy delivering humanitarian aid to nearly 275,000 victims besieged in Aleppo was hit.

Amid conflicting reports about casualties, the London-based Syrian Observatory for Human Rights claimed 12 people, including aid workers and truck drivers, were killed. Media reports said 18 of a total of 31 trucks were hit.

The UN on Tuesday suspended all aid-delivery operations in Syria following Monday’s airstrike.

“As an immediate security measure, other convoy movements in Syria have been suspended for the time being, pending further assessment of the security situation,” UN spokesman Jens Laerke told a press conference at the UN’s office in Geneva on Tuesday.

Also on Tuesday EU Foreign Policy Chief Federica Mogherini and Commissioner for Humanitarian Aid and Crisis Management Christos Stylianides issued a joint statement which described the airstrikes as "alarming violations of international humanitarian law".

Mogherini and Stylianides called on the Syrian government to end its air campaign against non-terrorist targets in Aleppo, and to allow the immediate and unhindered resumption of humanitarian access to all besieged areas and in particular to the people of Aleppo.

Anadolu Agency