ANKARA, March 27 (Xinhua) -- The Turkish and Russian presidents on Tuesday discussed an upcoming trilateral summit on Syria issues over phone, Turkey's state-run Anadolu Agency reported.

Recep Tayyip Erdogan and his Russian counterpart Vladimir Putin also discussed bilateral relations, the agency reported, citing anonymous Turkish presidential sources.

They also affirmed the determination to further develop bilateral ties, according to the sources.

Erdogan also offered condolences to Putin over a fire at a shopping mall in Siberia that killed at least 64 people, including 41 children.

The presidents of Turkey, Russia and Iran are set to meet in Turkey on April 4, to discuss the current situation in Syria and potential steps in the region.

On Sunday, Turkey announced that Syria's Afrin region had been taken under "full control" as part of ongoing military operation, which aims to clear the Kurdish People's Protection Units (YPG) in northern Syria.