Russia has denied its warplanes carried out air strikes on a village in eastern Syria on Sunday, which activists say killed dozens of civilians.
The Syrian Observatory for Human Rights said 53 people died in al-Shafah, while website DeirEzzor24 put the toll at 25.
Both said Russian aircraft, which are supporting Syrian pro-government forces battling so-called Islamic State (IS) in the area, were behind the attack.
But on Monday Russia’s defence ministry insisted it did not bomb al-Shafah.
“The Russian Aerospace Forces’ strikes in Syria target areas outside population centres, and only facilities of the international terrorist groups,” a statement said, according to Russian news agencies.
“The reports by the Syrian Observatory for Human Rights, which is based in Great Britain, about the alleged strikes by the Russian Aerospace Forces’ planes on the village of al-Shafah are yet another fake,” it added.
An earlier statement had announced that six Russian Tu-22M3 long-range bombers struck IS command posts and militant positions in Deir al-Zour province on Sunday.