Fresh Russian air strikes Thursday targeted bases held by a powerful Islamist rebel coalition including Al-Qaeda's affiliate in northwest Syria, a Syrian security source said.

"Air strikes from four Russian warplanes struck bases held by the Army of Conquest in Jisr al-Shughur and Jabal al-Zawiya in Idlib province," the source said, adding that arms depots held by "armed groups" in neighbouring Hama province were also targeted.