RIYADH, Saudi Arabia, (AP) – A former Guantanamo detainee who went through Saudi Arabia’s militant rehabilitation program and then joined al-Qaeda in Yemen has turned himself in to authorities, the government said.

Jabir Jubran al-Fayfi contacted Saudi authorities from Yemen to express his regret and readiness to surrender, the Interior Ministry said in statement Friday. Yemeni authorities arranged for his return.

The Saudi rehabilitation center has been a model for similar reform efforts in Yemen and elsewhere in the Middle East, using religious arguments and financial and other incentives to draw people away from extremism. Still, 11 of the 270 militants who passed through the Saudi program later rejoined al-Qaeda, the center says.

At least two of them went on to become top leaders in the Yemen-based Al-Qaeda in the Arabian Peninsula, which formed a year and a half ago with the help of Saudi militants driven across the border as a result of their country’s crackdown.

Al-Fayfi, too, joined al-Qaeda in Yemen sometime after his December 2006 release from Guantanamo and his participation in the Saudi rehabilitation program.

The terror network’s Yemen-based group has become one of al-Qaeda’s most dangerous franchises, attacking Western targets and security forces in that country. It also claimed responsibility for the failed attempt to bomb a Detroit-bound airliner in December with a would-be suicide bomber who had explosives sewn into his underwear.

The U.S. is backing Yemen’s counterterrorism campaign with money and other military assistance.

According to the U.S. government, al-Fayfi was first recruited at a mosque in Saudi Arabia and received two weeks of weapons training to fight Afghanistan’s opposition Northern Alliance from September to December 2001.

Al-Fayfi said he was at the front lines but denied firing a gun. He also said he never met any al-Qaeda members or trained at any terrorist camps in Afghanistan.

Available documents do not say where or when he was captured by U.S. forces.

After his detention at Guantanamo, he vowed never to participate in another jihad, according to documents released by Guantanamo’s Administrative Review Board.

Al-Fayfi said he had read a newspaper article that urged Muslims to join jihad in Afghanistan and did so because he felt he was not a faithful Muslim due to drug use, smoking and lack of prayer.

Upon his release from the U.S. military prison in Cuba, he said he wanted to go back home to Saudi Arabia to take care of his parents and resume his job as a taxi driver, the documents stated.

Al-Fayfi was transferred to Saudi Arabia on Dec. 13, 2006.