The court's intervention is troubling news for the White House, which has been battered by criticism of its treatment of detainees and was rebuked by the high court last year for holding enemy combatants in legal limbo.

The justices will decide if President Bush overstepped his authority with plans for a military trial for Osama bin Laden's former driver, who is being held at the U.S. military prison at Guantanamo Bay, Cuba. It would be the first such trial since World War II.

New Chief Justice John Roberts took himself out of the case because as an appeals court judge he backed the government in the same appeal. If Bush nominee Samuel Alito is confirmed, he could be a pivotal figure when the case is argued next spring.

The Pentagon announced Monday that five additional terror suspects at Guantanamo will face military trials on various charges including attacking civilians and murder. That brings to nine out of about 500 detainees at the facility who have been charged with criminal offenses.

Announcement of the court's move came shortly after Bush, asked about reports of secret U.S. prisons in Eastern Europe for terrorism suspects, declared anew that his administration does not torture anyone.

"There's an enemy that lurks and plots and plans and wants to hurt America again," Bush said during a news conference in Panama City with President Martin Torrijos. "So you bet we will aggressively pursue them but we will do so under the law."

"Anything we do to that end in this effort, any activity we conduct, is within the law. We do not torture," he said.

Bin Laden's former driver, Salim Ahmed Hamdan, has been in U.S. custody four years. He and three other terror suspects are to be tried before military officers.

Hamdan, who was captured in Afghanistan in November 2001, denies conspiring to engage in acts of terrorism and denies he was a member of al-Qaida. He has been charged with conspiracy to commit war crimes, murder and terrorism.

The Bush administration had urged the high court to stay on the sidelines until after the trials, arguing that national security was at stake. "The military proceedings involve enforcement of the laws of war against an enemy force targeting civilians for mass death," Solicitor General Paul Clement wrote in a filing.

Scott Silliman, a Duke University law professor, said the court in taking the case seemed to be making a statement that it would "define the perimeters of this war and what tools the president has available to him in this unique environment."

In 2004 the justices took up the first round of cases stemming from the war on terrorism. Justice Sandra Day O'Connor, who is retiring, wrote in one case that "a state of war is not a blank check for the president when it comes to the rights of the nation's citizens."

Arguments in the Hamdan case will be scheduled in time for O'Connor's successor to take part. Senate confirmation hearings are planned for January for Alito, who often has been deferential to government in his appeals court rulings.

Hamdan is among about 500 foreigners who were designated "enemy combatants" and imprisoned at the U.S. military prison in Cuba.

Guantanamo Bay has become a flash point for criticism of America overseas and at home. Initially, the Bush administration refused to let the men see attorneys or challenge their imprisonment in courts. The Supreme Court in 2004 said U.S. courts were open to filings from the men, although justices may be called on to clarify the legal rights of the detainees in a separate appeal.

"Guantanamo, in the eyes of the rest of the world, is a blot on American justice. Around the world, this will be as important if not more so than it is in the United States," said Stephen Saltzburg, a law professor at George Washington University who filed a brief urging the court to take Hamdan's case.

The case brings a new issue to the court - the rights of foreigners who have been charged with war crimes and face a trial before military officers with possible death sentences.

Retired military leaders, foreign legislators, historians and other groups had pressed the Supreme Court to review the case of Hamdan, who like many Guantanamo inmates began a hunger strike over the summer.

A district judge last November sided with Hamdan, a Yemeni who was 34 at the time. But the administration won an appeal before a panel of the United States Court of Appeals for the District of Columbia Circuit. The panel, including Roberts, said that the 1949 Geneva Convention governing prisoners of war does not apply to al-Qaida and its members.

The administration argued that it was unnecessary for the court to hear Hamdan's case because the Pentagon had relaxed the rules for tribunals, enabling more information to be shared with defendants, and because the government had changed the structure of the panels.

Hamdan's lawyer, Georgetown University professor Neal Katyal, said in a filing that "it is a contrived system subject to change at the whim of the president."

"With constantly shifting terms and conditions, the commissions resemble an automobile dealership instead of a legal tribunal dispensing American justice and protecting human dignity," he wrote.

Hamdan's attorneys may ask Roberts to participate in the case to avoid a 4-4 tie.

The case is Hamdan v. Rumsfeld, 05-184.