"The laws and constitution are designed to survive, and remain in force, in extraordinary times," the court said in its historic ruling Thursday, the third blow in four years to the government's case for trying "war on terror" suspects in military tribunals.

 

"Liberty and security can be reconciled; and in our system they are reconciled within the framework of the law," the court added.

 

The court ruled by five to four that prisoners in the US military prison in southeastern Cuba "have the constitutional privilege of habeas corpus."

 

President George W. Bush said he would abide by the decision but disagreed with it, and would consider seeking new legislation, while the Pentagon said it would examine the implications of the ruling.

 

"It's a Supreme Court decision, we'll abide by the court's decision. That doesn't mean I have to agree with it," Bush said from Rome during a European tour.

 

Speaking during a trip to Tokyo Fiday US Attorney General Michael Mukasey said the administration would continue military trials at Guantanamo Bay despite the decision.

 

"I think it bears emphasis that the court's decision does not concern military commission trials, which will continue to proceed," he told reporters.

 

He said the decision instead focused on the "procedures that the Congress and the president put in place to allow enemy combatants to challenge their detention."

 

Mukasey voiced disappointment at the decision, while saying he had not reviewed it in detail due to the time-zone difference between Washington and Tokyo.

 

"I'm disappointed with the decision insofar as I understand that it will result in hundreds of actions challenging the detention of enemy combatants to be moved to federal district court," Mukasey said.

 

Thursday's ruling should now give the prisoners and their legal teams the right to demand to know on what basis they are being held.

 

So far the Bush administration has refused to unveil the body of evidence to justify the prisoners' continued detention, saying it would endanger national security.

 

It was not immediately clear how Thursday's ruling would affect those 270 detainees still held in the jail, opened in January 2002 to deal with suspects rounded up in the US "war on terror."

 

"Some of these petitioners have been in custody for the past six years with no definitive judicial determination as to the legality of their detention," wrote Justice Anthony Kennedy in his 70-page majority ruling.

 

In a dissenting opinion, Chief Justice John Roberts said Congress's attempt "to balance the security of the American people with the detainees' liberty interests has been unceremoniously brushed aside."

 

Dissenting justice Antonin Scalia went further, writing that "America is at war with radical Islamists" and that the decision "will almost certainly cause more Americans to be killed."

 

Two-thirds of the 800 prisoners who have passed through Guantanamo's barbed-wire gates have been freed, mostly without charge, after several years in captivity.

 

Australian David Hicks is the only "war on terror" detainee to have so far been sentenced at Guantanamo after pleading guilty in a deal which allowed him to serve out his nine-month term at home.

 

Justice Department spokesman Peter Carr said the department was disappointed with the ruling and would review it, but noted that it did not directly affect the 20 Guantanamo detainees who currently face trial before military commissions.

 

"Military commission trials will continue to go forward," Carr said.

 

Those trials include Khalid Sheikh Mohammed, considered the mastermind of the September 11, 2001 terror attacks in the United States, and Osama bin Laden's driver, Salim Hamdan.

 

White House hopefuls Republican John McCain and his Democratic rival Barack Obama have both said they will close the prison, and Obama welcomed the decision saying it rejected "the Bush administration's attempt to create a legal black hole at Guantanamo."

 

"This is an important step toward re-establishing our credibility as a nation committed to the rule of law and rejecting a false choice between fighting terrorism and respecting habeas corpus," he said.

 

McCain said however he was concerned by the ruling, adding: "These are unlawful combatants. They are not American citizens."

 

The White House has repeatedly said it would shut Guantanamo down, but has failed so far to come with an alternative, or to find countries willing to take some prisoners, such as Muslim Uighurs from northwest China, who face repression at home.

 

The Supreme Court took up the issue of Guantanamo inmates in 2004 and again in 2006, ruling both times that detainees had a statutory -- legal but not constitutional -- right to contest their indefinite detention.

 

But Congress in 2006 simply passed new legislation that forbade them from seeking justice in a federal court until they are judged by a special military tribunal.

 

Amnesty International said Thursday's ruling was an "essential step forward towards the restoration of the rule of law."

 

"The time has come for the US government to finally bring its detention policies and practices in the 'war on terror' in line with international standards."