Russia has launched air strikes in Syria for a second day.
The strikes reportedly targeted positions in the north-west held by the Army of Conquest rebel alliance.
Russia said it had struck four Islamic State (IS) facilities overnight, and destroyed a "terrorist HQ" outside Idlib and a command post near Hama.
Russia carried out about 20 missions on Wednesday. The US fears they targeted non-IS opponents of Russia's ally, Syrian President Bashar al-Assad.
Thursday's strikes reportedly hit areas near the strategic town of Jisr al-Shughour, as well areas in Idlib province and Hama province further south, according to Lebanon's al-Mayadeen TV.
Rebel activists also reported strikes at Ghantu in Homs province, close to where some of Wednesday's strikes hit.
The Army of Conquest (Jaysh al-Fatah) alliance had made advances in the north-west in recent months, taking Idlib from pro-government forces.
The alliance includes the al-Nusra Front, al-Qaeda's affiliate in Syria, and the hardline Islamist group Ahrar al-Sham, as well as several more moderate Islamist groups.
All are opposed to IS and have fought bloody battles with the jihadist group.