Concerns have been raised about the welfare of an American journalist reportedly detained in Syria while covering the fighting there.
US State Department spokesman Patrick Ventrell said the US is trying to confirm reports that Austin Tice is being held.
The Czech government, which represents American interests in Syria, says it has information that Mr Tice is in custody but has yet to get confirmation from Syrian authorities.
Mr Tice is a freelance reporter working for The Washington Post and McClatchy newspapers. They said the Czech ambassador to Syria had said Mr Tice was alive.
Mr Ventrell asked the Syrians to respond quickly to Czech inquiries into Mr Tice’s whereabouts, well-being and safety.
He also urged all sides to the fighting to ensure the safety of journalists covering the conflict.