Syrian President Bashar Assad has made an unannounced trip to Iran, where he met with the supreme leader and other top officials to discuss the planned U.S. troop withdrawal and Turkey's efforts to set up a buffer zone in northern Syria, state media reported Monday.

Assad met with Supreme Leader Ayatollah Ali Khamenei and President Hassan Rohani on the rare trip abroad — his first to Iran since the civil war broke out in 2011. He has made two other trips since then, both to Russia.