Russian forces have killed 34 fighters and wounded more than 60 in air strikes on targets in Syria's Idlib governorate, Russia's Interfax reported late on Sunday, citing deputy head of Russian Reconciliation Center for Syria.

"The Russian Aerospace Forces carried out air strikes in the province of Idlib on targets of illegal armed groups involved in shelling the positions of Syrian government troops," Interax cited Rear Admiral Vadim Kulit as saying of the Saturday attack.

Kulit said that in 24 hours, positions of Syrian government troops were attacked seven times.

The Syrian army has blamed rebels, who it says are Islamist jihadists, for attacks on government-held areas in Idlib and Aleppo provinces and denies indiscriminate shelling of civilian areas under rebel control.

Opposition officials say both Moscow and Damascus are taking advantage of the world's preoccupation with Gaza conflict to escalate pounding of a region where more than three million inhabitants refuse to live under the rule of Bashar al-Assad.

Earlier, a source told Reuters that the United States has carried out two air strikes against Iran-aligned groups in Syria.