Members of the US Congress who toured Guantanamo Bay prison have said that conditions there are improving, despite renewed calls for its closure.
The delegation was shown cells used by the detainees
Their visit came at a time of growing concern that treatment of prisoners there is harming America's image.
More than 500 non-Americans - many captured during the war in Afghanistan and declared "enemy combatants"- are being detained at the facility.
Only four current inmates have been charged with any crime.
On Saturday 16 Representatives who sit on the House Armed Services Committee toured the prison, at a naval base on Cuba, during a one-day fact-finding trip.
California Democrat Ellen Tauscher, who has pushed for greater transparency about the facility, told AP news agency there had been progress since reports about alleged human rights abuses.
"The Guantanamo we saw today is not the Guantanamo we heard about a few years ago," she said.
"What we've seen here is evidence that we've made progress," said Sheila Jackson Lee, a Texas Democrat who believes the facility should close.
But legislators agreed that more needed to be done to ensure a legal framework to deal with detainees, some of whom have been held for three years without charge.
The group toured cell blocks and ate lunch with troops, a meal of chicken with orange sauce, rice and okra that was also served to inmates.
They watched the interrogation of three suspects, including one in which a detainee was read a Harry Potter book aloud for hours until he turned his back and put his hands over his ears.
None of the detainees was physically touched.
United Nations human rights investigators last week urged the US to allow them to inspect the facility.
They said there were "persistent and credible" reports of "serious allegations of torture, cruel, inhuman and degrading treatment of detainees".
In response, Vice-President Dick Cheney told CNN that the detainees were well treated, well fed and "living in the tropics".
White House officials say there are no plans to close the facility because, they say, the detainees are too dangerous to release while the fight against terrorism continues.