WASHINGTON, Dec. 18 (Xinhua) -- U.S. President Barack Obama on Friday urged Turkish President Recep Tayyip Erdogan to take additional steps to de-escalate tensions with Iraq, the White House said.

While speaking by phone with Erdogan, Obama urged Turkey to continue to withdraw its military forces from northern Iraq, and reinforced the need for Turkey to respect the sovereignty and territorial integrity of Iraq, the White House said in a statement.

The crisis between Turkey and Iraq sparked earlier this month when reports said a Turkish training battalion equipped with armored vehicles was deployed near the city of Mosul to train Iraqi paramilitary groups in fighting the extremist group Islamic State (IS).

Over the phone, Obama and Erdogan agreed to work together on diplomatic efforts between the U.S., Turkey, and Iraq to reduce tensions and to coordinate military efforts against IS.

The two leaders also discussed intensifying cooperation on Syria, including joint efforts to strengthen the moderate Syrian opposition and step up pressure on IS, as well as continued efforts to create conditions for a negotiated solution to the conflict.