White House spokesman Robert Gibbs defends reformed military commissions
Civil liberties groups have reacted angrily to US President Barack Obama's decision to revive military trials for some Guantanamo Bay detainees.
Mr Obama has previously denounced the Bush-era judicial system, but in a statement said new safeguards would ensure suspects got a fairer hearing.
New rules include rejecting statements obtained from harsh interrogations and limitations on using hearsay evidence.
There are still 240 detainees at the US base in Guantanamo Bay, Cuba.
Barack Obama branded the original military trials an enormous failure
Mr Obama halted the controversial military commissions as one of his first acts on taking office in January, saying the US was entering a new era of respecting human rights.
"It's disappointing that Obama is seeking to revive rather than end this failed experiment," said Jonathan Hafetz, a national security attorney at the American Civil Liberties Union.
"There is no detainee at Guantanamo who cannot be tried and shouldn't be tried in the regular federal courts system. This is perpetuating the Bush administration's misguided detention policy."
Kenneth Roth, head of Human Rights Watch, said: "By resurrecting this failed Bush administration idea, President Obama is backtracking dangerously on his reform agenda."
On the campaign trail last year, Mr Obama had branded the military commissions "an enormous failure".
But in the statement issued on Friday, he said he had supported their use as one avenue to try detainees, and in 2006 had voted in favour of them.
He said he had opposed the tribunals used by George W Bush's administration because they had failed to establish a legitimate legal framework and undermined swift and certain justice.
The extra safeguards for detainees include a ban on evidence obtained by harsh interrogation; restrictions on hearsay evidence; giving detainees more leeway to choose their own lawyers and protecting detainees who refuse to testify, the statement said.
Mr Obama said he was seeking more time so that the new procedures could be implemented.
"These reforms will begin to restore the commissions as a legitimate forum for prosecution, while bringing them in line with the rule of law," he said.
"This is the best way to protect our country, while upholding our deeply held values."
But Geneve Mantri, of Amnesty International, said Mr Obama's message was confusing.
"It was clear from his announcements soon after he reached the White House what he was going to do," he said.
"Now it is somewhat confusing what the administration's standard is or what their policies are."
Zachary Katznelson of Reprieve, which represents a number of Guantanamo Bay detainees, told the BBC that the president was making a "fundamental mistake".
"He is taking a gravely, truly flawed system, tinkering at the edges and hoping that the world is somehow going to see this as legitimate, as open, as fair - it's not going to happen," he said.
In contrast, Mr Obama found support for his decision among his opponents.
"I am pleased that President Obama has now adopted this view," said Republican Senator John McCain, who lost the presidential election to Mr Obama.
Ari Fleischer, who was George W Bush's first press secretary, said President Obama "should acknowledge his campaign criticisms were wrong".
"With some minor changes, he really is following the same path President Bush pursued," he said.
The BBC's James Coomarasamy in Washington says that although some are disappointed, for others it is further evidence of Mr Obama's pragmatic style of leadership, one that recognises the need to balance the change he has promised with the reality he has inherited.
Mr Obama has said he wants the Guantanamo Bay camp closed by 2010.
Shortly before his announcement, US officials said that Algerian detainee Lakhdar Boumediene had left Guantanamo Bay for France.
Mr Boumediene was arrested in Bosnia in 2001 and was held for seven years. He was cleared of any wrongdoing in November.
US MEDIA REACTION TO OBAMA'S DECISION
Obama officials have been dispatched to insist to journalists (anonymously, of course) that Obama's embrace of "new and improved" military commissions is neither inconsistent with the criticisms that were voiced about Bush's military commission system nor with Obama's prior statements on this issue. It is plainly not the case that these "modifications" address the core criticisms directed to what Bush did, nor is it the case that Obama's campaign position on this issue can be reconciled with what he is now doing.
President Obama, and the country at large, is finding out that George W Bush's most controversial policies were not born of ideological delusion, American arrogance, or missionary zeal. They were imperfect but sound (with the exception of our ties to Riyadh) responses to complicated threats. But the validation of the last president runs a very distant second to the most compelling aspect of all this: the drama over CIA interrogations and Guantanamo will hopefully serve to set the administration on a more serious national security course. And it would be helpful if the American public finally dropped moral outrage as the preferred mode of political argumentation.
Let me see if I've got this right: The previous extra-legal system wasn't up to snuff because it wasn't codified enough? The new! improved! Obama-era secret trials will be better because they are swifter and more certain? Seriously? The introductory statement alone, to me, undermines the whole premise that this is by any stretch an acceptable substitute for time-tested United States criminal code prosecution.
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