|Crowley, centre, resigned over comments he made regarding the Pentagon's detention of a US soldier [Reuters]
US state department spokesman PJ Crowley has resigned from his post following controversial comments involving the whistleblowing website WikiLeaks.
The news on Sunday came three days after Crowley was reported to have criticised the Pentagon's treatment of detained US soldier Bradley Manning.
Crowley said the defence department's handling of Manning, who is accused of leaking thousands of confidential US documents to WikiLeaks, was "stupid" and "counterproductive".
He was speaking at a private event, after being asked about claims that Manning is being harshly treated in US military custody. The state department said the comments were his personal opinion.
But in a resignation statement on Sunday, Crowley said he took full responsibility for the "impact" of his remarks.
"The unauthorised disclosure of classified information is a serious crime under US law," he said.
"My recent comments regarding the conditions of the pre-trial detention of Private First Class Bradley Manning were intended to highlight the broader, even strategic impact of discreet actions undertaken by national security agencies every day and their impact on our global standing and leadership.
"The exercise of power in today’s challenging times and relentless media environment must be prudent and consistent with our laws and values.
"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."
'Served with distinction'
Hillary Clinton, the US secretary of state, said she had accepted Crowley's resignation with "regret".
"PJ has served our nation with distinction for more than three decades, in uniform and as a civilian," she said in a statement.
"His service to country is motivated by a deep devotion to public policy and public diplomacy, and I wish him the very best."
Clinton named principal deputy assistant secretary Michael Hammer to replace Crowley temporarily.
Allegations of torture
Bradley Manning is facing life in prison if found guilty of more than 22 charges, which include aiding the enemy.
|Manning is accused of leaking US secrets [EPA]
Manning allegedly downloaded and distributed more than 250,000 confidential state department cables as well as
a deluge of Iraq and Afghanistan war logs. Thousands of the documents have been published on the WikiLeaks website.
While thousands of the cables have been released, the bulk of those downloaded have not been made public.
The army has not ruled out charging others in the case, pending results of a continuing review. Army leaders have suggested that there may have been supervisory lapses that allowed the breach to occur.
Trial proceedings against Manning have been on hold since July, pending the results of a medical inquiry into Manning's mental capacity and responsibility.
Manning is being held in maximum custody at the Marine Corps base in Virginia. His supporters say his solitary confinement amounts to torture, and are calling on the UN to investigate.
Barack Obama, the US president, said on Friday that he had been assured by the Pentagon that its treatment of Manning was appropriate.
Asked at a news conference about Crowley's remarks, Obama said Manning's treatment reflects the department of defence's concerns about the young soldier's safety.
Al Jazeera's Rosiland Jordan, reporting from the White House, said the administration has been trying to deal with the problem of leaks.
"In this case, we're talking about a president who has said that the US government does not engage in anything resembling torture."
But she said the detention of Manning has raised questions about whether the administration is actually keeping its word.
"Certainly the other message that is being sent to other members of the government with the resignation of PJ Crowley is that if think that you might be privy to information that we don't want out in the general public, you need to keep your mouth shut."
Source: Al Jazeera and agencies