TEHRAN, Sept. 7 (Xinhua) -- Russian President Vladimir Putin said on Friday that terrorist groups in Syria's Idlib carried out "provocative" acts.

Putin said that the terrorist groups were using drones against the targets under the control of the Syrian government. They are also preparing for the use of chemical weapons in Idlib.

On Friday, Turkish President Recep Tayyip Erdogan and Putin arrived in Iran's capital Tehran to attend a tripartite summit as part of Astana process which seeks solution to the civil war in Syria.

The meeting comes amid accelerated efforts of international community, and it will be the third summit of the leaders after the previous ones in Russian resort city of Sochi and Turkish capital Ankara.

Turkey recently has stepped up for diplomatic and military demarche as the Syrian government forces are planning a massive operation to eliminate all extremist groups in Idlib after the successful recapture of rebel-held parts of western and southern Syria.

As a result, President Erdogan met Iranian Foreign Minister Mohammad Javad Zarif in Ankara on Aug. 29. Turkish Foreign Minister Mevlut Cavusoglu met his Russian counterpart two times in August, while Turkish intelligence and military chiefs paid a visit to Moscow as well.