Fifth of ex-Gitmo inmates return to fight: US

Nearly 20 percent of detainees released from Guantanamo Bay are believed to have returned to the battlefield, the White House said in a letter to House of Representatives Speaker Nancy Pelosi seen by AFP Tuesday.

The letter, from President Barack Obama's counterterrorism advisor John Brennan, acknowledges that the "intelligence community assesses that 20 percent of detainees transferred from Guantanamo are confirmed or suspected of recidivist activity."

That 20 percent includes 9.6 percent of released detainees who are confirmed to have returned to militant activities and another 10.4 percent whom U.S. intelligence "suspects, but is not certain, may have engaged in recidivist activities," Brennan wrote.

Among detainees known to have returned to terrorism are some who joined al-Qaeda in the Arabian Peninsula, a terror group based in Yemen that claimed responsibility for planning a failed Christmas Day terror attack on a U.S. plane.

Obama pledged in early January that he would not return released Guantanamo detainees to Yemen until the "unsettled situation" in the impoverished Arab nation had been resolved.

Brennan's letter, first reported by ABC News, notes that all the known cases of former Guantanamo detainees joining terrorist groups involved prisoners released by former president George W. Bush's administration.

There were "no confirmed or suspected recidivists among detainees transferred during this administration, although we recognize the ongoing risk that detainees could engage in such activity," his letter said.

On Jan. 10, Democratic Senator Dianne Feinstein, chair of the Senate Intelligence Committee, said that dozens of former detainees held at Guantanamo, a third of them from Yemen, had returned to combat.

The Obama administration has pledged to close the controversial detention facility for terror suspects located on a U.S. naval base on Cuba's southern tip.