James Foley, 39, was last seen Nov. 22 in Idlib province heading for the Turkish border in a car, GlobalPost said. A Syrian later told a reporter in Turkey by telephone that he had seen Foley's car intercepted by a group of men armed with Kalashnikovs and described the correspondent being forced into their car.
The identity of the kidnappers is unknown. Richard Engle, an NBC news correspondent and three members of his team, were abducted in the same area in December and freed when their captors ran into a checkpoint manned by members of a rebel group.
Foley has reported for GlobalPost from Afghanistan and Libya as well as Syria. In 2011, he spent more than a month imprisoned in Libya after he and other reporters were captured by forces loyal to Moammar Gadhafi.
Philip Balboni, founder of GlobalPost, described Foley as a "brave and dedicated reporter." Balboni said the company has been working with U.S. officials and Syrian groups to free Foley.
Foley's family has set up a website to campaign for his release.
"We want Jim to come safely home, or at least we need to speak with him to know he's okay," his father, John Foley, said. "Jim is an objective journalist and we appeal for the release of Jim unharmed. To the people who have Jim, please contact us so we can work together toward his release."