Turkish President Recep Tayyip Erdogan (R) shakes hands with US Secretary of State Rex Tillerson ahead of a meeting at the presidential complex in Ankara on Thursday (Friday in Manila).
"As I said before, our relations are at a critical turning point", Tillerson said. "Ours is not an alliance of convenience". "We were either going to correct this and continue our relations or we were going to go into a much more worse position".
Tillerson is in Turkey on a two-day visit.
Combined forces of the Turkish Army and allied Free Syrian Army militias have driven Kurdish fighters from another two towns in Syria's northwestern Afrin region, Al-Masdar News reports.
Ankara has long called for YPG forces to move east of the Euphrates river in Syria.
The US and Turkey, whose forces are at loggerheads in northern Syria, have agreed to try to defuse the crisis.
Mr Tillerson said issues around Manbij would receive priority in the talks.
As the talks got underway, dozens of Turkish demonstrators marched to the building where the meeting took place, waving Turkish flags, to protest USA support to the YPG.
While Ankara tries its utmost to eliminate the presence of the organization in the region, Washington provides it with all kinds of weapons, ammunition and military training.Ankara's expectation of its North Atlantic Treaty Organisation ally is very simple: To immediately stop supplying arms and take back the weapons it has provided to a terrorist organization that attacks Turkey.
"It is clear that the United States probably have such a strategy to settle in Syria forever, with its armed forces, just as they want to do in Iraq and Afghanistan, despite all promises made".
Other sources of conflict have been a recent defense deal struck between Turkey and Russian Federation over the purchase of an S-400 anti-missile system The deal has raised concerns by the West over deepening ties, as well as Russia's integration into NATO's military architecture.
"We find ourselves at a bit of a crisis point in the relationship", Mr Tillerson told a news conference after a meeting with Foreign Minister Mevlut Cavusoglu on Friday morning.
"We want to consult with Turkey and make sure they at least understand what may be at risk with this transaction", Tillerson said. "We have an emergency need for air defences and the Russian Federation came up with an attractive proposal for us", he said.
While recognizing Turkey's right to secure its borders, Tillerson urged Ankara to show restraint in its military operation in Syria.
Turkey is livid over America's military support for the Kurdish-led Syrian Democratic Forces.
Associated Press writer Lorne Cook in Brussels contributed.