On Wednesday, Foreign Minister Mevlut Cavusoglu said ties were harmed by Washington's failure to extradite Gulen and US support for Syria's Kurdish YPG militia and its PYD political arm.
Turkey's foreign ministry has summoned a senior U.S. diplomat to express Ankara's "discomfort" over Washington's support for Syrian Kurdish fighters, state media reported.
They also highlighted the important outcome of the summit meeting between His Majesty and the Turkish president in the Turkish capital Ankara last month, and the momentum it provided to increase cooperation and coordination between the two countries. Turkey also sees the YPG as an extension of the outlawed Kurdistan Workers Party (PKK), and believes it is waging an insurgency against the Turkish state. In May 2017, Deputy Prime Minister Nurettin Canikli called the supply of weapons to the Kurdish forces "unacceptable".
Ankara's ire isn't just centered on the United States.
Russian helicopter crashes in Syria, 2 pilots die
On January 3, Russia's Defense Ministry said that one of its military helicopters crashed in Syria, killing both pilots aboard. The Britain-based watchdog Syrian Observatory for Human Rights, said most of the airstrikes were carried out by Russian jets .
In May of past year, as President Donald Trump and Erdogan met, a brawl erupted in Washington outside the Turkish ambassador's residence.
Syrian government's ongoing offensive in Idlib province will be a test for the alliance of Russia, Iran and Turkey, three regional powers that support different actors on the battlefield.
However, Syrian regime forces, with Russian backing have stepped up attacks trying to regain control of the area controlled by the rebels.