A federal judge says terror suspects held by U.S. authorities at Guantanamo Bay (search) in Cuba must be allowed to meet with lawyers and that their conversations cannot be monitored.

U.S. District Judge Colleen Kollar-Kotelly said in her ruling on Wednesday that administration "attempts to erode this bedrock principle" of attorney-client privacy were backed by "a flimsy assemblage" of arguments.

The Supreme Court ruled in June that the 600 foreign-born men then held in the Navy-run prison camp could challenge their captivity in American courts.

Kollar-Kotelly, a former Justice Department attorney named to the bench by President Clinton (search), said that would be impossible without legal help.

"They have been detained virtually incommunicado for nearly three years without being charged with any crime. To say that (detainees') ability to investigate the circumstances surrounding their capture and detention is 'seriously impaired' is an understatement," she wrote.

She also said it was impossible for the men "to grapple with the complexities of a foreign legal system and present their claims to this court" without attorneys, access to a law library and fluency in English.

"We are reviewing the decision," Justice Department spokesman John Nowacki said late Wednesday.

Michael Ratner, president of the New York Center for Constitutional Rights which represents some of the detainees, called it "a wonderful vindication of what the Supreme Court said they had a right to have: access to lawyers."

"The government had dug in here as if the Supreme Court ruling did not exist. It took a federal judge to tell them that's not the case," he said.

Multiple cases have been filed in federal court in Washington on behalf of Guantanamo detainees.

Kollar-Kotelly's decision, the most significant since the Supreme Court's June ruling, came in the case of three Kuwaiti nationals who have been held since shortly after the terrorist attacks on Sept. 11, 2001.

Government lawyers had agreed to let the men see attorneys, but argued that was not legally required. The government also wanted to monitor the meetings and review attorneys' notes and mail — something Kollar-Kotelly said would infringe on the detainees' attorney-client privilege.

The government had said the three detainees were particular risks and should have their attorney meetings monitored. Thomas Wilner, the attorney for the three and nine other Kuwaitis, said Wednesday he hoped to arrange meetings soon.

"The court is acutely aware of the delicate balance that must be struck when weighing the importance of national security against the rights of the individual," Kollar-Kotelly wrote.

"However the government has supplied only the most slender legal support for its argument, which cannot withstand the weight of the authority surrounding the importance of attorney-client privilege."

Brian D. Boyle, a lawyer for the Justice Department, had told the judge earlier that allowing the conversations to go unmonitored would pose a national security risk if the lawyers intentionally or inadvertently disclosed classified information.

He said detainees might seek to use their attorneys to pass along dangerous information.

The judge said in Wednesday's decision that attorneys must have appropriate security clearance to meet with detainees, and that they cannot discuss the conversations with anyone, unless the government agrees.

More than 500 men from 40 countries are being held on suspicion of links to al-Qaida or the fallen Taliban regime of Afghanistan.

Robert Turner, a law professor at the University of Virginia, said the government may have legitimate concerns about lawyer meetings.

"A number of serious things could result if a sympathetic lawyer were to have unmonitored access," he said.