U.S. President Donald Trump said it was important to keep a U.S. military presence in Iraq so that Washington can keep a close eye on Iran "because Iran is a real problem," according to a CBS interview to be broadcast on Sunday.

The Republican president lamented "endless wars" in Syria and Afghanistan in an interview with CBS' "Face the Nation" and made clear he wants to reduce the costly U.S. military presence in those countries despite warnings against such moves from his military advisers and spy chiefs.

The United States could rely heavily on intelligence work in Afghanistan, he said, and respond to developments in Syria from U.S. bases in neighboring Iraq.