Lawyers filed petitions in federal court in Washington yesterday on behalf of five men detained for the last two years at the U.S. military prison in Guantanamo Bay, Cuba, demanding that the government release them or prove that it has reason to continue their captivity.

The Center for Constitutional Rights called the filings only the first round of habeas corpus petitions it would file on behalf of as many as 53 Guantanamo detainees, some of whom have been held for more than two years without attorneys.

The move came after a Supreme Court ruling that granted detainees the right to contest their incarcerations in U.S. courts. "This is just the beginning," said Barbara Orlansky, the organization's deputy legal counsel.

Also yesterday, government attorneys agreed during a telephone conference with lawyers for 12 detained Kuwaitis that the Pentagon would "move as expeditiously as possible" to allow them access to their clients at Guantanamo Bay, said Tom Wilner, one of the attorneys who took part.

U.S. District Judge Colleen Kollar-Kotelly urged the government to move quickly in granting the defense lawyers access.

"I'm happy the government is finally acting reasonably, and we're grateful for that," said Wilner, who sued on behalf of the Kuwaitis two years ago.

Maj. Michael Shavers, a Defense Department spokesman, said yesterday the petitions do not alter the government's effort to determine how to comply with the ruling.

"The Department of Defense, the Justice Department and the administration are still working together to determine how we're going to comply with the Supreme Court direction," Shavers said. "No decision has been made at this point."

In Rasul v. Bush, the Supreme Court ruled that the 595 alleged al Qaeda and Taliban fighters held at the U.S. Navy base at Guantanamo Bay have the right to ask a U.S. judge to set them free or justify why they are being detained.

Orlansky said her group scurried to file "as many petitions as were humanly possible" after the Supreme Court ruling. She contended that the government cannot make a case against these five detainees or many others. Some were arrested in Bosnia and Gambia, yet were accused of armed conflict in Afghanistan.

Staff writer John Mintz contributed to this report.