Speaking to reporters in a conference call from Washington, D.C., Case said he understands that the Bush administration was going to portray the detention facility in the best possible light during his visit, but said he felt the delegation "had the run of the place" and that Guantanamo Bay is "a secure and up-to-date facility."

"Under the circumstances I think GTMO (the military's acronym for the base) is being operated well and in a way that is necessary to the safety and security of our country and in a way that is humane," Case said. "I saw a protocol for treatment of these detainees that does provide them with good food and good healthcare and access to legal counsel, and I saw in the interrogation itself, which we did witness, carefully monitored questioning and techniques that were nowhere close to abusive."

Case said he was able to ask prison guards questions without supervision and discuss questioning techniques with interrogators.

After a tour of the prison for suspected terrorists and enemy combatants on Saturday, Case said yesterday that the United States has made progress in improving conditions and protecting detainees' rights. He said he saw some of the antiquated facilities that were used at the prison in 2002, but said the $100 million renovation of the facility has significantly improved living conditions there.

Case's delegation, led by Rep. Duncan Hunter, R-Calif., witnessed interrogations, toured cellblocks and ate the same lunch given to detainees on the first congressional visit to the prison since criticism of it intensified in the spring.

A Senate delegation also was visiting last weekend.

Last week Case joined 170 of his colleagues in introducing a bill that would establish an independent commission, similar to the 9/11 commission, to investigate allegations of detainee abuse at Guantanamo Bay, Abu Ghraib and elsewhere.

He said he believes the public perception of Guantanamo is worse than the reality and that an independent commission overseeing the facility would go a long way in calming fears about the treatment of detainees.

"I think what's appropriate is that we have some independent third-party commission to take a look over the shoulders of the Department of Defense. I don't believe such a commission, given what I saw and heard yesterday, would find anything that hasn't been found already," he said.

Republicans and Democrats alike fear the prison at the U.S. Navy base in eastern Cuba is hurting the United States' image because of claims that interrogators have abused and tortured inmates. The White House and Pentagon say conditions are humane and detainees are well-treated.

The prison opened in January 2002 to house foreigners believed to be linked to al-Qaida or the ousted Taliban in Afghanistan. U.S. officials hoped to gather intelligence from the detainees after the U.S. invasion of Afghanistan in October 2001.

Bush declared the detainees "enemy combatants," affording them fewer rights than prisoners of war under the Geneva Conventions. Some detainees have been held for three years without being charged with any crimes.