Suspected Russian jets kill at least 20 civilians and wounds dozens when they dropped bombs on two residential buildings in a besieged rebel enclave east of the Syrian capital, residents and a war monitor says.

Russia's air force has destroyed a large column of Islamic State fighters on their way to the Syrian city of Deir al-Zor, killing over 200 militants, Russian news agencies cites Russia's Defence Ministry as saying.

Egyptian President Abdul Fattah al-Sisi has described claims that militants linked to Islamic State (IS) brought down a Russian airliner as "propaganda".