DAMASCUS, Syria — An American citizen who disappeared seven months ago into former Syrian President Bashar Assad’s notorious prison system was suddenly discovered Thursday outside Damascus after being released and handed over to rebel forces, Syria’s new authorities said.

The political affairs office of the Islamist group Hayat Tahrir al-Sham, the rebel group that led the lightning offensive to topple Assad’s government, said the group had secured the release of U.S. citizen Travis Timmerman. In interviews with media in Syria, Timmerman said he was imprisoned after crossing from Lebanon into Syria on a Christian pilgrimage.

He appeared to be among the thousands of people released from Syria’s sprawling military prisons this week after rebels reached Damascus, overthrowing Assad and ending his family’s 54-year rule.

“We affirm our readiness to cooperate directly with the U.S. administration to complete the search for American citizens disappeared by the former Assad regime,” the group said, adding that a search was underway for Austin Tice, an American journalist who went missing in Syria 12 years ago.

As footage emerged online Thursday of Timmerman, looking disheveled and disoriented as rebels led him out of a family’s home near Damascus, some initially mistook him for Tice.

In the video, Timmerman could be seen lying on a mattress under a blanket. A group of men in the video said that he was being treated well and would be safely returned home.

A Syrian family told The Associated Press they found Timmerman barefoot on a main road in the countryside of Damascus early on Thursday. He appeared cold and hungry so they brought him back to their home.

“I fed him and called a doctor,” said Mosaed al-Rifai, the 68-year-old waste collector who first found Timmerman.

Al-Rifai said it was hard to communicate because of the language barrier but it seemed Timmerman had been held by an internal security agency. A few hours after al-Rifai discovered him, rebels arrived at the family’s house to pick him up, he said.

Mouaz Mostafa, the executive director of the Syrian Emergency Task Force, a U.S.-based nonprofit group, said he met Timmerman at the house and arranged for a car to take him to Damascus, where the new authorities gave the ex-detainee food and water and brought him clothes and shoes. Timmerman had lice in his long, unkempt hair, Mostafa said, and reported walking for 13 miles barefoot before being discovered.

Timmerman — now recovering until the rebels can figure out how to hand him to U.S. authorities — was planning to get to Jordan after his release to obtain a new passport, Mostafa said.