Presidential Spokesman İbrahim Kalın discussed developments in Syria and Libya over the phone with U.S. national security adviser Robert C. O'Brien, Turkish presidential sources said early Friday.

Kalın and O'Brien also exchanged views on an international conference that will be held Sunday in Berlin on the Libyan crisis and highlighted the importance of maintaining the cease-fire agreement in the de-escalation zone in Idlib, Syria, said the sources, who asked not to be named due to restrictions on speaking to the media.

Germany is inviting countries concerned with the Libyan issue to attend the Berlin conference in an attempt to reach a political solution to the conflict.

Kalın and O'Brien also agreed on making the necessary suggestions to the relevant parties for the implementation of the cease-fire in Libya.

The oil-rich North African country has been wracked by bloody turmoil since a 2011 NATO-backed uprising killed longtime dictator Moammar Gadhafi, with multiple foreign powers now involved.

Since the ouster of late ruler Gadhafi in 2011, two seats of power have emerged in Libya: one in eastern Libya supported mainly by Egypt and the United Arab Emirates and the other in Tripoli, which enjoys U.N. and international recognition.