"That poses a direct threat to our national security," Ibrahim Kalin said speaking at 18th Doha Forum "Identifying a European Role: Navigating Polarization across the MENA Region."

According to Anadolu news agency Kalin said Turkey's measures were not just for own interest but also for Syria's territorial integrity.

Turkish presidential spokesman said the U.S. presence in Syria went beyond its purpose and became "another theater for proxy games in the region."

"They say that now they are in Syria for three main reasons: One is the enduring defeat of Daesh. Number two is to provide stability and secure Syria's territorial integrity and number three is, now they say it publicly, to get Iran and its forces out of Syria," Kalin said.

Kalin recalled his last meeting with his U.S. counterpart, during which he reported saying, "Look I can understand the first two goals, but good luck with the third one."

"That means Syrian issue is no longer about Syrian issue," Kalin added.

On Wednesday, Erdogan said that within days Turkey would launch an operation in Syria, east of the Euphrates, near Turkey’s borders.

Reporter’s code: 50101