The U.S. identified the freed American as Peter Theo Curtis of Massachusetts and said he now was safe and outside of Syria. The United Nations said it helped with the handover to U.N. peacekeepers in a village in the Israeli-annexed Golan Heights and that Curtis was released to American authorities after a medical checkup.
The administration provided no details about the circumstances of his abduction or his release. It was not known what prompted Curtis' release.
"He seems to be in good health," Hardigg told The Associated Press. "We are deeply relieved and grateful for his return and the many people who have helped us secure his freedom. At the same time, we are thinking constantly of the other hostages who are still held and those working to help them be freed. We want to do everything we can to support their efforts."
Secretary of State John Kerry said Jabhat al-Nusrah, an al-Qaida-linked militant group fighting the government of Syrian President Bashar Assad, had held Curtis. "Finally, he is returning home," Kerry said in a statement.
He added that over the past two years, Washington had "reached out to more than two dozen countries asking for urgent help from anyone who might have tools, influence, or leverage to help secure Theo's release and the release of any Americans held hostage in Syria."
Another American, journalist James Foley, was beheaded by Islamic State militants who released a video last week blaming his death on U.S. airstrikes against their fighters in Iraq. Foley's captors had demanded $132.5 million (100 million euros) from his parents and political concessions from Washington. Neither obliged, authorities say.
A candlelight vigil and special church service were held for Foley in his hometown of Rochester, N.H. over the weekend.
The British government, like the U.S., adheres to a longstanding policy against paying ransoms to extremists.
A senior Obama administration official said last week the Islamic State had made a "range of requests" from the U.S. for Foley's release, including changes in American policy and posture in the Mideast.
© 2018 Cox Media Group.