Washington ? At least 10 detainees released from the Guantanamo Bay prison after U.S. officials concluded they posed little threat have been recaptured or killed fighting U.S. or allied forces in Pakistan and Afghanistan, according to Pentagon officials.

One of the repatriated prisoners is still at large after taking leadership of a militant faction in Pakistan and aligning himself with al-Qaida, Pakistani officials said. In telephone calls to Pakistani reporters, he has bragged that he tricked his U.S. interrogators into believing he was someone else.

Another of the returned captives is an Afghan teenager who had spent two years at a special compound for young detainees at the military prison in Cuba, where he learned English, played sports and watched videos — privileges unavailable to most other captives — informed sources said. U.S. officials believed they had persuaded him to abandon his life with the Taliban, but recently the young man, now 18, was recaptured with other Taliban fighters near Kandahar, Afghanistan, according to the sources, who requested anonymity because they were discussing sensitive military information.

The cases of the relapsed militants demonstrate the difficulty Washington faces in deciding when alleged al-Qaida and Taliban detainees should be freed, amid pressure from foreign governments and human rights groups who have denounced U.S. officials for detaining the Guantanamo Bay captives for years without due process rights, military officials said.

“Reports that former detainees have rejoined al-Qaida and the Taliban are evidence that these individuals are fanatical and particularly deceptive,” said a Pentagon spokesman, Navy Lt. Comm. Flex Plexico. “From the beginning, we have recognized that there are inherent risks in determining when an individual detainee no longer had to be held at Guantanamo Bay.”

The latest case emerged two weeks ago when two Chinese engineers working on a dam project in Pakistan’s virtually lawless Waziristan region were kidnapped. The commander of a tribal militant group, Abdullah Mehsud, 29, told reporters by satellite phone that his followers were responsible for the abductions.

Mehsud, who lost a leg in a land-mine explosion and wears a prosthesis, said he spent two years at Guantanamo Bay after being captured in 2002 in Afghanistan fighting alongside the Taliban. When he was captured, he was carrying a false Afghan identity card, and while in custody he maintained the fiction that he was an innocent Afghan tribesman, he said. American officials never realized he was actually a Pakistani with deep ties to militants in both countries, he added.

“I managed to keep my Pakistani identity hidden all these years,” he told Gulf News in a recent interview.

The 10 or more returning militants are but a fraction of the 202 Guantanamo Bay detainees who have been returned to their homelands.