Peter Theo Curtis was handed over to UN peacekeepers in the village of al-Rafid, Quneitra, on Sunday. He has since been turned over to representatives from the US government after undergoing medical check-up, the UN said.

Curtis' family thanked both the governments of the US and Qatar, as well as others who helped negotiate his release.

According to a statement from his family, Curtis was captured in October 2012 and was reportedly held by the al-Nusra Front terrorist group or by splinter gangs allied with the al-Qaeda-affiliated group.

US Secretary of State John Kerry said he was relieved Curtis was returning home, before laying blame on al-Nusra Front for the kidnapping.

"We are all relieved and grateful knowing that Theo Curtis is coming home after so much time held in the clutches of [al-Nusrah Front], he said.

Kerry also said the US was using "every diplomatic, intelligence, and military tool" available to release other Americans held hostage.

Footage of the American was released on June 30, showing a disheveled Curtis with long hair and beard, but appearing to be in good health.

Speaking in a video obtained by Al Jazeera, Curtis read from a prepared script stating his name and profession, saying he was a journalist from Boston, Massachusetts.

According to the Committee to Protect Journalists (CPJ), at least 67 journalists have been killed in Syria since the start of the foreign-backed insurgency war in the Arab country, highlighting the risks of reporting from there.

Dozens of journalists covering the foreign-hatched war have been seized since the conflict began in March 2011, with many others still missing.

NTJ/MB