Neither Russian nor Syrian planes bombed an aid convoy in Syria's Aleppo, Moscow said, as outrage mounted over an attack that the Red Cross said killed about 20 people.
"The air forces of Russia and Syria did not conduct any strikes against the UN aid convoy in the southwestern outskirts of Aleppo," defence ministry spokesman Igor Konashenkov said in a statement carried by Russian news agencies on Tuesday.
Konashenkov said the attack the previous night doesn't appear to have been from an air strike.
The Syrian Civil Defence, a volunteer rescue group known as the White Helmets that operates in rebel-held areas, posted images of several vehicles on fire. A video of the attack showed huge balls of fire against the night sky as ambulances arrived on the scene.
| Syria: Air raid hits aid convoy as ceasefire ends
The Russian military "carefully studied the video recordings of the so-called activists from the scene and found no signs that any munitions hit the convoy", Konashenkov said.
"Everything shown on the video is the direct consequence of the cargo catching fire, and this began in a strange way simultaneously with militants carrying out a massive offensive in Aleppo."
The United Nations has suspended all aid convoys to Syria following the attack on aid trucks, which could amount to a "war crime", according to UN official Jens Laerke.
Air raids rocked northern Syria's Aleppo province on Tuesday, hours after 18 lorries in the UN convoy were hit in an area west of Aleppo city.
Secretary-General Ban Ki-moon, speaking at the UN General Assembly in New York, called those who attacked the trucks "cowards".
"Powerful patrons that keep feeding the war machine also have blood on their hands," Ban added.
The United States said it was unclear if it was a Russian or Syrian plane that hit the 31-truck UN aid convoy late on Monday, but officials placed the blame on Moscow, a key ally of embattled Syrian President Bashar al-Assad.
"The Americans are firmly blaming the Russians, saying they're not reining in Damascus," Al Jazeera's Stephanie Dekker reported from Gaziantep, on the Syrian border.
The convoy was part of a routine inter-agency dispatch operated by the Syrian Arab Red Crescent.
Following Monday's aid convoy strike, the UN said it was suspending all convoy movement in Syria, and Peter Maurer, the International Committee of the Red Cross president, said the attack could have "serious repercussions" on humanitarian work in the country.
READ MORE: ISIL shoots down Syrian military jet, kills pilot
The new wave of bloodshed came after the Syrian army unilaterally declared the end of a week-long truce brokered by the US and Moscow. The government and the rebels traded blame over the collapse, each accusing the other side of hundreds of breaches.
"If this callous attack is found to be a deliberate targeting of humanitarians, it would amount to a war crime," said Stephen O'Brien, the top UN humanitarian official, adding the warring parties had been told about the aid convoy.
The Syrian Arab Red Crescent was also hit during Monday's strike, as was a warehouse run by the group.
SARC volunteers were among at least 28 civilians killed in the Aleppo area in the first hours after violence resumed following the formal end of the truce, according to the UK-based Syrian Observatory for Human Rights.
The rebel-held area east of Aleppo city, home to some 300,000 people, has been cut off from aid deliveries since July despite the ceasefire.
Ground battles between pro-government forces and rebel fighters raged on Tuesday on the southwestern outskirts of Aleppo city near the strategic Ramosa military complex, according to the Syrian Observatory, as air raids pounded the northern province.
"There's been ... renewed air strikes in Aleppo, in the eastern, rebel-held part of the city. Also further north in Handarat. Also reports of air strikes in Talbiseh, in Homs, further south," Dekker reported.
READ MORE: Messages from ISIL territory ask forgiveness for murder
The US State Department said that it was ready to work with Russia to strengthen the terms of the agreement and expand deliveries of humanitarian aid.
Spokesman John Kirby said Russia, who the US has deemed responsible for ensuring the Syrian government compliance, should clarify the Syrian position.
A Russian Foreign Ministry statement late on Monday night appeared to signal the deal could still be salvaged.
Dekker said a meeting of the International Syria Support Group, chaired by Russia and US, was due to take place in New York on Tuesday.
"The language coming out of the US is that they want to try and extend the cessation of hostilities. We've heard nothing from Lavrov, nothing officially from the Russians," said Dekker.
"It really does explain why Syrians are so sceptical. Because every time they are told that something is in the works and that this is the beginning of a political process to end this war, that’s now into its sixth year, and every time it fails."
The ceasefire came into effect on September 12. Under terms of the agreement, the successful completion of seven days of calm and humanitarian aid deliveries would be followed by an ambitious second-stage plan to set up a joint US-Russian coordination centre to plan military strikes against the Islamic State of Iraq and the Levant (ISIL) and a Jabhat Fateh al-Sham, formerly the al-Qaeda-linked al-Nusra Front.
But from the start, the truce was beset by difficulties and mutual accusations of violations.
Source: Al Jazeera News And Agencies