Human rights lawyers filed court challenges on behalf of nine Guantanamo Bay (search) detainees Friday, citing this week's Supreme Court (search) ruling and pressing the government to justify its detention of the terror suspects or let them go.

A federal court was urged to rule that the nine detainees were being unlawfully held at the military prison in Cuba. They were the first cases filed since the Supreme Court's ruling this week that the prisoners may use U.S. courts to contest their detentions.

"This is the beginning of trying to enforce precisely what the Supreme Court mandated as a way to obtain justice," said Jeffrey Fogel, legal director of the New York Center for Constitutional Rights (search). "The first step is that the government has to respond."

Challenges were filed on behalf of two British citizens, three French citizens, a German Turk, a Jordanian Palestinian refugee, an Iraqi refugee and a Canadian.

They question whether some of the men are in poor mental health after long stretches of being held in isolation.

More lawsuits are expected on behalf of other prisoners. About 600 men from more than 40 countries are being held on suspicion of links to Al Qaeda or the fallen Taliban (search) regime of Afghanistan. Some of the detainees have been at the prison for more than 21/2 years, with little or no contact with the outside world. Just four have had access to lawyers.

Attorneys for the nine detainees said in court filings Friday that the government has exceeded its constitutional authority and asked the court to "declare that the prolonged, indefinite, and restrictive detention of (the detainees) is arbitrary and unlawful."

The Bush administration contends the men are "enemy combatants" who pose a threat to America and can be held without legal rights. The Supreme Court rejected the administration's argument that the detainees could not take their complaints to U.S. courts.

"No decision has been made on how we are going to comply with the Supreme Court ruling," said Maj. Michael Shavers, a Pentagon spokesman. "The ruling wasn't simple and while we certainly will comply, the exact manner is still being discussed."

A half-dozen law firms worked on Friday's filings, along with the Center for Constitutional Rights, the nonprofit legal organization which had represented two Australian detainees in the case that led to Monday's Supreme Court ruling.

The justices said federal courts can hear the cases of Guantanamo Bay detainees, but did not describe a process.

On Thursday, the human rights group wrote to Defense Secretary Donald H. Rumsfeld, asking for access to 53 prisoners held at the naval base.

The lawyers involved haven't been able to meet with any detainees in Cuba, but Fogel said they had authorization from prisoners' families. He said the detainees are:

— British citizens Moazzem Begg, who was captured in Pakistan, and Feroz Abbasi.

— Murat Kurnaz, a Turkish citizen with German residency captured in Pakistan.

— French citizens Mourad Benchallali, Nizar Sassi and Ridouane Khalid, all captured in Pakistan.

— Jamil El-Banna, a Jordanian/Palestinian refugee residing in the United Kingdom, captured in Gambia, and Bisher Al-Rawi, an Iraqi refugee residing in the United Kingdom, captured in Gambia.

— Canadian Omar Khadr, who was 15 years old when captured two years ago in Afghanistan.

Gitanjali Gutierrez, an attorney in Newark, N.J., who worked on the filing for Begg and Abbasi, said the detainees are not aware of the Supreme Court ruling and the speedy petitions filed on their behalf. But their families are.

"It gives them hope. For them, it restores a sense of American principles and law. Now there is a process for them to have contact with their family members," she said. "It gives the detainees a chance to be heard."