U.S. State Department spokesman Philip Crowley resigned on Sunday over his comment on the Army's treatment of a U.S. soldier suspected of leaking U.S. diplomatic cables to the whistle-blower website WikiLeaks.

"It is with regret that I have accepted the resignation of Philip J. Crowley as Assistant Secretary of State for Public Affairs," Secretary of State Hillary Clinton said in a statement.

"Given the impact of my remarks, for which I take full responsibility, I have submitted my resignation as Assistant Secretary for Public Affairs and Spokesman for the Department of State," Crowley was quoted as saying in the statement.

Crowley was reportedly saying in a talk at Massachusetts Institute of Technology that the treatment of jailed former intelligence analyst Bradley Manning "is ridiculous and counterproductive and stupid."

Private Manning was arrested in May last year and accused of downloading several hundred thousand of diplomatic cables and classified reports on the wars in Iraq and Afghanistan and providing them to WikiLeaks.

The release of the diplomatic cables in particular has put the U.S. government in an awkward position and strained its relations with some foreign governments.

Reports said that starting on March 2, Manning was forced by prison guards to sleep without clothing at night out of fear that he might harm himself. Crowley said he did not understand Defense Department official's reasons for imposing such a treatment, but he said later he was expressing his personal views.

When a reporter raised Crowley's comment at a White House press conference last Friday, President Barack Obama replied that he had actually asked the Pentagon "whether or not the procedures that have been taken in terms of his confinement are appropriate and are meeting our basic standards. They assure me that they are."

Obama said: "I can't go into details about some of their concerns, but some of this has to do with Private Manning's safety as well."

When pressed about whether he disagreed with Crowley, Obama said: "I think I gave you an answer to the substantive issue."

Crowley, 60, was sworn into office on May 2009 as Assistant Secretary of State for Public Affairs. He spent 26 years in the U. S. Air Force and held office at the White House.