Foreign Minister Mevlüt Çavuşoğlu held a phone call with his U.S. counterpart Mike Pompeo, diplomatic sources said Saturday.

According to the sources, the ministers discussed the latest developments in Syria.

Speaking in Abu Dhabi later in the day, Pompeo said there were still many details to be worked out with Turkey but he was optimistic that a "good outcome" can be achieved that protects Turkey from legitimate terror threats, after speaking to the Turkish foreign minister.

Pompeo also said the withdrawal of U.S. troops from Syria was a "tactical change" and does not alter U.S. military capacity to counter Daesh and Iran.

Earlier this week Pompeo told reporters in Iraq that U.S. President Donald Trump is determined to withdraw American soldiers from Syria and his decision is very clear, addressing concerns as to whether Turkey's refusal to fulfill any preconditions to the withdrawal would put the move at risk.

Pompeo's remarks came after U.S. National Security Adviser John Bolton said that as a precondition for the U.S.' withdrawal, the protection of YPG terrorists must be assured, which drew ire from Turkish politicians, including top government officials.

However, Bolton later said that the U.S.' withdrawal would be subject to defeating Daesh remnants, and Turkey assuring the safety of fighters allied with the U.S., i.e. the Syrian Democratic Forces (SDF), which is dominated by the YPG.

President Recep Tayyip Erdoğan has called Bolton's remarks unacceptable, saying Turkey could not accept the U.S.' condition of protecting YPG terrorists, the Syrian affiliate of the PKK.

Ankara has repeatedly told Washington that the YPG is not different from the PKK as the groups were intertwined, and partnering with one terrorist group to fight another was not acceptable. Washington, however, has continued to support the YPG, despite the U.S. listing the PKK as a terrorist organization.