Media tours Fort Leavenworth, where WikiLeaks suspect is being held

(CBS/AP) FORT LEAVENWORTH, Kan. - The Army today opened the doors of Fort Leavenworth, the Kansas military prison where WikiLeaks suspect Army Pfc. Bradley Manning is currently being held, in an unusual attempt to combat allegations that the military has been mistreating Manning.

Army Pfc. Bradley Manning was moved last week from the Marine Corps brig in Quantico, Va., to the Joint Regional Correctional Facility at Fort Leavenworth amid criticism over his treatment and confinement. At Quantico, Manning was held in solitary confinement for 23 hours a day, stripped naked each night and given a suicide-proof smock in which to sleep.

Senior Pentagon officials insist those conditions met basic standards of confinement and were appropriate given the seriousness of the charges against Manning. They say Manning was transferred because Fort Leavenworth is better suited to long-term detainment, which Manning likely faces as his complex case unfolds.

Thursday's tour, which barred the taking of photos or video, was intended to show the conditions inmates live in at the medium-security prison, which opened late last year and houses about 150 other inmates, including several awaiting trial. It was built near the U.S. Disciplinary Barracks, the military's maximum-security prison for inmates sentenced to at least five years' confinement or death.

"Clearly, Pfc. Manning is an unusual circumstance," Army spokesman Col. Tom Collins said.

But Manning's supporters, who see him as a whistleblower, not a traitor, say the tour would only give a sanitized glimpse at life in the military prison, not the oppressive conditions Manning has been subjected to since his arrest last year.

"This tour is an effort to relieve the pressure, but we will not let up until Manning is treated properly," said Kevin Zeese, who operates the Bradley Manning Support Network. He said it was clear that pressure from Manning's supporters and international observers was having an effect on President Barack Obama's administration.

Manning is accused of leaking hundreds of thousands of documents to the anti-secrecy website WikiLeaks, including Iraq and Afghanistan war logs, confidential State Department cables and a classified military video of a 2007 Apache helicopter attack in Iraq that killed a Reuters news photographer and his driver.

Manning faces nearly two dozen charges, including aiding the enemy, a crime that could bring the death penalty or life in prison.

His transfer to Leavenworth came a bit more than a week after a U.N. torture investigator, Juan Mendez, complained that he was denied a request to make an unmonitored visit to Manning. Pentagon officials said he could meet with Manning, but it is customary to give only the detainee's lawyer confidential visits.

Mendez said a monitored conversation would be counter to the practice of his U.N. mandate.

A few days later, a committee of Germany's parliament protested about Manning's treatment to the White House. And Amnesty International has said Manning's treatment may violate his human rights.

Tom Parker, a policy director at Amnesty International, said, "The conditions that he was reported to be held in at Quantico were extremely harsh and could have damaged his mental health."

Obama and senior military officials have repeatedly contended that Manning is being held under appropriate conditions given the seriousness of the charges against him.