MIAMI – The two men given the responsibility for finding a way to empty the prison camps at Guantanamo Bay of the last 164 captives visited the U.S. Navy base in southeast Cuba earlier this week and issued a strong rebuke of the status quo.

“For us, it is not merely about treating detainees humanely, it is about ensuring that our operations reflect the values for which America stands,” said Paul Lewis, the Pentagon’s new special envoy for the closure of Guantanamo, or Gitmo, who traveled to the base Monday with his State Department counterpart for secret meetings at the prison camps.

Mostly members of the Army, the 2,100-strong staff of the prison compound that holds the last 164 captives, just six of them facing war crimes trial, soldier at the base under the motto of “Safe, Humane, Legal and Transparent” detention. After Monday’s mission to the camps, the military had no comment on the visit in which Lewis adapted the motto to argue that it was time to put the prison camp out of business.

“Our troops continue to perform admirably in extremely difficult circumstances,” Lewis said just days after the Army captain in charge of one maximum-security compound told BBC Radio that her troops were suffering twice the rate of post-traumatic stress disorder of other American troops serving in other areas of warfare.

In May, President Obama announced creation of the two special envoy jobs assigned to close the prison at a time of a surging hunger strike at the camps that encompassed more than 100 captives. Monday, 15 of the men were still on fasts protesting their detention, and all 15 were approved for restraint-chair tube feedings, said Navy Cmdr. John Filostrat, the prison spokesman.

Also Monday, the two men who had separately visited the prison camps before made their first joint trip to the base under a veil of secrecy. Military spokesmen would not comment on any aspects of the visit.

The visit also comes at a time of debate inside Congress on whether to ease harsh restrictions on Guantanamo prisoner transfers that have thwarted Obama’s closure ambition, notably by forbidding the relocation of the captives at the base in Cuba to U.S. soil.

Lewis’ counterpart, State Department envoy Clifford Sloan, said after returning to Washington that the closers are “moving ahead on the President’s commitment to close the detention facility responsibly, and we are making progress.”