MOSCOW: The Russian Ministry of Defence said on Thursday that its planes had carried out four air strikes against militants in Syria's Idlib region, the RIA news agency reported.
The Russian military said that the Turkish army had asked for its help to protect Turkish troops by striking "terrorists in Idlib".
Earlier, the Syrian army and its allies shelled rebel-held areas of northwest Syria on Thursday and attacked a Turkish observation post, Ankara and a monitoring group said, despite Russia saying it and Turkey had brokered a new cease-fire.
However, Turkish Foreign Minister Mevlut Cavusoglu on Thursday said a ceasefire had not been fully secured in Syria's northwestern Idlib province, despite the announcement by Moscow.
"We are working hard with Russia to stop these attacks. It is not possible to say a complete ceasefire has been secured," Cavusoglu told a press conference with his French counterpart Jean-Yves Le Drian.
Turkey’s Defense Ministry said Syrian government forces carried out what it assessed to be a deliberate attack, firing 35 mortar shells at one of its observation posts in the de-escalation zone in Idlib, wounding three Turkish soldiers and damaging equipment and facilities.
Ankara has made representations to Moscow about the incident, the defense ministry said. It did not say when exactly the attack happened.
The Syrian Observatory for Human Rights, a war monitor, said air strikes on rebel-held areas paused overnight, but resumed on Thursday morning. They targeted the area around Khan Sheikhoun, an opposition-held town in southern Idlib province, it said, adding that the insurgents had also fired artillery at government forces.
On Wednesday, the Russian military said that Moscow and Ankara had agreed a full cease-fire in the northwest, centered on Idlib, but it did not say how long the truce would last.
The Syrian government launched its offensive against northwest Syria, the last major stronghold of the rebellion against it, in late April.
Russia is Damascus’s main ally in the civil war between Syrian President Bashar Assad and rebels seeking to oust him, using its warplanes to bombard opposition areas. Turkey backs some insurgent groups.
Moscow and Ankara had agreed a partial truce last September that called for an end to bombardment of the area and for Ankara to pull heavy weapons and militant groups from frontline areas.
The fighting has caused hundreds of thousands of people, many of whom had already been displaced, to flee further north and seek shelter along the Turkish border.
Turkey has pushed Russia to rein in the government’s offensive while Russia has said Turkey must curb the militant groups that dominate in Idlib.