President-elect Barack Obama is moving on a campaign pledge to close the Guantánamo Bay prison, preparing to issue an executive order in the first days of his administration on one of the most controversial developments of the Bush Administration.

The order to close the prison, which houses suspected terrorists at the US Naval base in Cuba, will be the first grand gesture of the President-elect in an effort to distance himself from the outgoing Bush Administration.

An adviser to Mr Obama, who will be inaugurated as the next US president in Washington a week today, said that he is expected to issue the order within his first week in the White House.

"There is going to be an executive order on closing down Guantánamo," the adviser told Reuters.

The practicality of closing the controversial prison is much more complicated and Guantánamo Bay is unlikely to shut right away. Mr Obama has already admitted that closing the facility would take some time, saying last weekend that it would be “a challenge” to close it even within the first 100 days of his administration.

"[It] is more difficult than I think a lot of people realise," Mr Obama said in an interview on US television.

"You have a bunch of folks that have been detained, many of whom may be very dangerous who have not been put on trial...and some of the evidence against them may be tainted even though it's true."

But, the President-elect said, closing the prison was non-negotiable for him. "We are going to close Guantánamo and we are going to make sure that the procedures we set up are ones that abide by our constitution," Mr Obama said.

"We will send a message to the world that we are serious about our values."

The Obama administration will have to decide how to replace the prison and how to revise detention and interrogation practices in keeping with the President-elect's vows for more humane policies.

At his last news conference yesterday, outgoing President George W. Bush said that many of the countries that criticised America for keeping the prison open had been unwilling to take on the detainees who were held there.

About 255 men are still held at the US-run naval base in Cuba, a symbol of aggressive interrogation methods that exposed the US to allegations of torture. Most have not been charged with a crime and their detention in the facility has enraged the Muslim world.

Washington has cleared 50 of the detainees for release but cannot return them to home countries because of the risk that they might be tortured or persecuted there. Around 500 others have been freed or transferred to the supervision of other governments since 2002.

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