Washington ? President Bush stood by his embattled defense secretary, Donald Rumsfeld, on Monday, praising him as a strong, courageous leader who is doing a “superb job.”

“Our nation owes you a debt of gratitude,” Bush said.

His message was clear: The White House is closing ranks around Rumsfeld, even as new reports of prisoner abuse surface and the Pentagon prepares to share with Congress still-private pictures and videos of the abuse.

“We remain in close contact with the Pentagon on these matters,” White House press secretary Scott McClellan told reporters pressing him on the prospect that the new pictures would be released.

The president viewed more than a dozen of the graphic images at the Pentagon, McClellan said, and his reaction was “one of deep disgust and disbelief that anyone who wears our uniform would engage in such shameful and appalling acts.”

Rumsfeld, who appeared before congressional panels Friday, did not speak during the president’s visit, leaving the White House to answer the increasing calls for his resignation.

“Accountability here is essential — even if that means relieving top leaders from duty in time of war,” the Army Times said in a stinging editorial aimed at Rumsfeld and Gen. Richard Myers, chairman of the Joint Chiefs of Staff.

Sen. Joseph Biden of Delaware, the ranking Democrat on the Senate Foreign Relations Committee who has called for Rumsfeld’s resignation, said that he didn’t care now if the defense secretary “stands on his head in the corner.”

“It’s less important what happens to him than that we demonstrate to the world that we understand the gravity of this and move on,” he told the CBS Early Show.