"I think it's going to take some time and our legal teams are working in consultation with our national security apparatus as we speak to help design exactly what we need to do," Obama said on ABC News programme ‘This week’.

"It is more difficult than I think a lot of people realise," the president-elect explained in what analysts say is an indication that he now plans to take a more measured approach than what he had advocated during his campaign.

The Guantanamo Bay prison holds some 250 ‘war on terror’ suspects, mostly from Afghanistan.

"Part of the challenge that you have is that you have a bunch of folks that have been detained, many of whom may be very dangerous who have not been put on trial or have not gone through some adjudication," Obama said.

He said they need to "balance a process that adheres to rule of law, habeas corpus, basic principles of Anglo-American legal system, by doing it in a way that doesn't result in releasing people who are intent on blowing us up".

But Obama unequivocally said that the infamous detention centres will be closed and vowed that his administration will ‘not torture’ terror suspects.

"I don't want to be ambiguous about this. We are going to close Guantanamo and we are going to make sure that the procedures we set up are ones that abide by our Constitution.