Deputy Associate Attorney General J. Michael Wiggins was responding to a question from Democratic Senator Joseph Biden when he said “it is our position that, legally, they can be held in perpetuity.”

Senator Biden drew the response when asking whether detained suspects might continue to be held indefinitely as Washington wages its so-called ‘war on terror’.

“If there is no definition as to when the conflict ends, that means forever, forever, forever these folks get held at Guantanamo Bay,” the Senator said.

Earlier, the committee’s top Democrat, Senator Patrick Leahy, said the United States may face terrorism “as long as you and I live.”

He questioned Brigadier General Thomas Hemingway, the officer in charge of the Guantanamo Bay military trials, about the possibility of prisoners being kept indefinitely without charge.

“I think that we can hold them as long as the conflict endures,” Brig Gen Leahy replied.

Of the 520 or so Guantanamo detainees, referred to as ‘enemy combatants’ by the White House, only four have been formally charged.

Most have been in detention for more than three years at the facility that was set up in January 2002, following the September 11 attacks in the US.

Criticism has mounted in opposition to the policy, amid recent allegations of abuses committed by interrogators at Guantanamo Bay.

The latest revelations published by Time Magazine this week detailed tactics allegedly employed on Mohammed al-Qahatani, suspected of being the 20th hijacker for the September 11 plot.

“Guantanamo Bay is an international embarrassment to our nation, to our ideals, and it remains a festering threat to our security,” Senator Leahy said.

The US Supreme Court ruled a year ago that Guantanamo detainees have the right to seek their release in federal court.

But decisions by lower courts have been contradictory, leading to what the committee chairman, Senator Arlen Specter, called a ‘crazy quilt’ of judgements.

“I think it would be tremendously helpful if the Congress and the administration came together with some general statutory language to help define what’s going on at Guantanamo Bay, to better define what an enemy combatant is, to make sure that due process is afforded,” Republican Senator Lindsey Graham said.