Planes conducted 237 combat sorties, striking 875 "terrorist" targets in the provinces of Aleppo, Latakia, Homs, Hama and Deir Ezzor, the defence ministry said in a statement.
A ministry spokeswoman told AFP the strikes had taken place from Monday to Wednesday.
The ministry said the military action backed a major offensive by Syrian government forces and pro-regime fighters in the northern Aleppo region.
The offensive led to the liberation of the Shiite towns of Nubol and Zahraa, "which had been under siege for four years, it said.
The Britain-based Syrian Observatory for Human Rights said Thursday that at least 21 civilians, including three children, had been killed by Russian strikes in rebel-held districts of Aleppo.
The United States demanded today, a day after the peace talks were suspended, that Russia halt its bombing campaign in the war-torn country.