"The United States will maintain a conditions-based and IS-focused military presence in Syria. As part of that presence, we will continue to train local security forces in Syria," Tillerson said.

"We are keenly aware of the legitimate security concerns of Turkey, our coalition partner and NATO ally," Tillerson said. "We will continue to be completely transparent with Turkey about our efforts in Syria to defeat IS [Daesh], and we stand by our NATO ally in its counterterrorism efforts."

Tillerson announcement comes after Turkish President Recep Tayyip Erdogan called on the US earlier in the day to "stop this theater with Daesh in Syria," adding that a decision by the US to continue to fund the Syrian Kurdish YPG militia would affect Turkey's decisions.

The situation in the region escalated earlier this year, after US Col. Thomas Veale said that the US-led coalition had been training the Kurdish Syrian Democratic Forces (SDF) to create a 30,000-strong force to maintain security along Syria's borders.

Following the revelation, Turkey launched an operation dubbed "Olive Branch" in Syria's Kurds-dominated Afrin. The operation is carried out against Kurdish SDF-affiliated People's Protection Units (YPG), which Ankara believes have links to the Kurdistan Workers’ Party (PKK), designated as a terrorist organization in Turkey.

Reporter’s code: 50101