Britain's Foreign Office said Moazzam Begg and Feroz Abbasi were among six prisoners at Camp X-ray in Guantanamo Bay, Cuba, whom President Bush designated on Thursday for military trial.

The news angered Begg's father Azmat. "I don't know why he has been trapped," he told Sky News. "Our government has got to take very serious steps toward his release. This military tribunal -- I don't have any trust in it."

Senior U.S. defense officials have refused to give names or nationalities of the six but said they had attended "terrorist" training camps and may have been involved in financing Saudi-born Osama bin Laden's al Qaeda network.

Human rights campaigners questioned whether they would receive a fair trial.

"The U.S. Department of Defense will appoint the judges and prosecutors, control the defense and make up the rules of the trial," said Stephen Jakobi, Director of Fair Trials Abroad.

"We have got to the point where the hallmarks of the Cuban exercise are those of a failed and cynical public relations stunt," he added.

A Foreign Office spokesman said: "This is the very beginning of the process. They have only been designated at this stage. It is not automatic that any person so designated will end up before a military commission."

The European Commission urged the United States to avoid applying the death penalty to the six captives.