Kremlin claims that a civilian aid convoy destroyed in Syria with 20 dead was being used by rebels as cover to move heavy weapons is demonstrably false, analysts in Russia said, amid growing tensions between Moscow and Washington over the recent incident.

But despite the threat to joint efforts to implement a ceasefire in Syria, Russia's Foreign Minister Sergei Lavrov said work will continue towards ending the five-year civil war.

The Conflict Intelligence Team (CIT), an independent group of Russia-based analysts, used geo-location technology to analyse drone footage Moscow released to support its claim that a rebel vehicle towing a mortar was travelling with the convoy before it was hit by presumed Russian or Syrian warplanes near Aleppo, the Times reported on September 23.

Analysis of the sun’s position and satellite images of the location point to the footage having been shot five hours before the attack, suggesting a ruse to deflect the outcry over the incident away from Moscow and Damascus, which deny involvement in the strike on September 19.

“It is speculation at this stage, but I think it is most likely that they destroyed what they presumed to be a military target and then tried to cover it up,” said Kirill Mikhaylov, one of the authors of the CIT report. “The same thing happened in eastern Ukraine when the rebels claimed on social media that they had knocked down a Ukrainian transport plane and then tried to retract that after it turned out to be the MH17 passenger liner.”

CIT said the Russian claim that there was no evidence of an airstrike and that rebel ground forces must have launched the attack was wrong. The group cited imagery of vehicles and medical supply boxes at the scene that were heavily damaged by shrapnel fragments, as well as showing the tail fin of an aerial weapon.

They also said pro-Assad Twitter accounts, citing Syrian military sources, had announced a successful Russian attack on an “ammunition convoy” belonging to Fateh al-Sham Front, formerly the Nusra Front, on that day. This suggested a case of mistaken identity and a cover up, the group said.

Washington blamed Moscow for the attack, whether or not Russian planes were involved, saying it was responsible under the recent ceasefire for reining in Syrian President Bashar al-Assad’s government forces. The United Nations said the attack on the convoy delivering food to civilians trapped in Aleppo would constitute a war crime if found to be deliberate.

Russia's Lavrov emphatically denied the involvement of Russian or Syrian government aircraft in the incident, which threatens to wreck new cooperation between his country and the US towards finding a settlement in the conflict.

“Our military have already made the statements that our aviation did not work there. The Syrian aviation could not work as the attack on the convoy occurred during the hours of darkness,” Lavrov said while attending a recent session of the UN General Assembly in New York.

Earlier, Russian Defence Ministry spokesman Igor Konashenkov said analysis of video footage from drones of the strike shows that militants were following the convoy. “It is clearly seen in the video that a terrorists' pickup truck with a towed large-caliber mortar is moving along with the convoy,” he said. He later added that Russia had observed the arrival in the same area of a US Predator drone - an unmanned aerial vehicle capable of launching missile strikes.

The convoy of 31 trucks was hit in the area of Urum al-Kubra, west of Aleppo, prompting the UN to halt its aid operations in Syria.

Despite the international tensions over the incident and a prior supposedly erroneous US bombing of Syrian government forces that killed around 60 troops, Lavrov pledged to continue efforts to settle the conflict. “Nothing has happened and we will continue our consultations,” the minister said after a meeting of the International Syria Support Group in New York on September 22. “We will continue our work to guarantee the ceasefire in Syria.”