Iranian foreign minister Javad Zarif's visit to Turkey, during which he was expected to discuss the Syrian conflict, has been postponed, a Turkish foreign ministry official said on Tuesday.

The official gave no further details.

Turkey and Iran back opposing sides in the wars in Syria and Yemen, but their economic interdependence has kept relations broadly on track.

Turkey has stepped up its involvement in Syria's civil war in recent weeks, calling for a protected zone that could relieve pressure on rebels fighting against forces loyal to President Bashar al-Assad, a close ally of Iran.

Zarif was expected in Beirut later on Tuesday. He was also expected to visit Moscow next week, Tass news agency quoted the Iranian embassy as saying on Monday.