"Let them have their borders, but I do not think our soldiers should be there for the next 15 years guarding a border between Turkey and Syria when we cannot guard our own borders," Trump said while addressing the Values Voters Summit's Faith, Family, and Freedom Gala dinner on Saturday.

On Wednesday, Turkish President Recep Tayyip Erdogan announced the launch of a military operation in northern Syria against the Islamic State terrorist group (IS, banned in Russia) and the Kurdistan Workers' Party, which Ankara designates as terrorists. The air component of the operation has begun the same day in the Ras al-Ain town of Al Hasakah province, while the land operations have been launched shortly after.

The Turkish offensive in northern Syria is part of Ankara's long-standing goal to clear its border area of both Kurdish militia and IS terrorists, and create a so-called safe zone along the cleared line. The military operation has already resulted in civilian deaths on both sides of the border.

Damascus views the operation as a violation of Syria's territorial integrity. The offensive was also condemned by the Western countries.