HOUSTON -

The father of an American journalist who went missing while working in one of Syria's most volatile regions says he believes his son is being held by the Syrian government but hasn't received confirmation.

From his home in Houston, Marc Tice said Thursday he's working with his son's editors at The Washington Post and McClatchy Newspapers.

Austin Tice worked as a freelance journalist for both media organizations. They're reporting that the Czech ambassador to Syria told Czech television that her sources say he's alive and in government detention near Damascus.

The 31-year-old former Marine recently spent time with rebel fighters in Syria. He hasn't been heard from in nearly three weeks.

A State Department official says the U.S. is seeking information through Czech officials, who represent U.S. interests in Syria.