MOSCOW (Reuters) - The Russian Defence Ministry on Tuesday rejected assertions that an aid convoy near Aleppo had been shelled or struck from the air the previous day, saying it had caught fire instead.

The United Nations suspended all aid shipments into Syria on Tuesday after what it said was a deadly attack on the convoy carrying humanitarian supplies, as a week-old U.S.-Russian sponsored ceasefire collapsed in renewed violence.

Russia challenged that version of events.

“We have studied video footage from the scene from so-called ‘activists’ in detail and did not find any evidence that the convoy had been struck by ordnance,” Igor Konashenkov, a spokesman for the ministry said in a statement.

“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.”

Konashenkov said damage to the convoy visible in footage was instead the direct result of its cargo catching fire which he said had “oddly” occurred at the same time as militants had started a big offensive in nearby Aleppo.

Russia had stopped monitoring the convoy after it had delivered its aid after which he said its whereabouts had only been known to militants on the ground.

That same evening, Konashenkov said the militant group formerly known as Nusra Front, had begun a big offensive backed by tanks, artillery and other heavy equipment.

He said that only the White Helmets civil defence rescue group could answer who was responsible for what happened to the convoy.

“Only representatives of the ‘White Helmets’ organisation close to the Nusra Front who, as always, found themselves at the right time in the right place by chance with their video cameras can answer who did this and why,” said Konashenkov.