Russian fighter jets hit 63 targets in Syria in the past 24 hours, the defense ministry said Sunday, as Moscow intensifies a campaign it says is aimed against the Islamic State jihadist group.

"Su-34, Su-24M and Su-25SM planes carried out 64 sorties from the Hmeimim airbase against 63 targets in the provinces of Hama, Latakia, Idlib and Raqa," the defense ministry said in a statement.

AFP quotes the Russian military as claiming that the air strikes had destroyed 53 positions used by the "terrorists", as well as a command post, four training camps and seven ammunition depots.

Russia said its campaign in the war-torn country was rattling IS fighters, claiming that radio intercepts showed "growing panic" among them.