WASHINGTON DC, United States?US on Monday defended its record probing civilian deaths and abuse in Iraq after graphic revelations in leaked secret documents triggered concern around the world.

The whistleblower website WikiLeaks released an unprecedented 400,000 classified US documents, which recount widespread torture in Iraqi prisons and purport to show 15,000 more civilian deaths than previously disclosed.

General George Casey, the top officer in the US Army who earlier headed forces in Iraq for three of the bloodiest years in the war, denied that the United States "turned a blind eye" to abuse of prisoners.

"That's just not the case. Our policy all along was when American soldiers encountered prisoner abuse, it was to stop it and then report it immediately up the American chain of command and up the Iraqi chain of command," he said.

Casey also denied undercounting civilian deaths, saying that US forces regularly inquired at morgues about death tolls.

"It doesn't ring true with me. We actively went out and tried to understand the impact of both our actions and the militant groups' actions on civilians," he told reporters.

State Department spokesman Philip Crowley also rejected WikiLeaks' accusations, saying that the United States has conducted human rights training of Iraqi forces.

"That's one of the reasons why we've continued to have military forces in Iraq, to help with ongoing training of Iraqi security forces. And we believe that we've seen their performance improve over time," Crowley said.

WikiLeaks, run by shadowy Australian-born computer hacker Julian Assange, said the documents showed a total of 109,032 deaths in Iraq between 2004 and 2009?66,081 of them civilians.

Britain, the main US ally in the Iraq war, said there was "no place" for mistreatment of detainees. A spokesman for Prime Minister David Cameron said: "We do as a matter of course investigate any allegation that is made against our troops."

Britain's Deputy Prime Minister Nick Clegg on Sunday described allegations against US-led forces in the WikiLeaks documents as "extraordinarily serious" and "quite shocking."

The Gulf Cooperation Council, which comprises six US-friendly Arab monarchies, urged the United States to "open a serious and transparent investigation" into possible "crimes against humanity."

Human rights groups also called for a probe, with New York-based Human Rights Watch saying that the United States may have broken international law if it knowingly transferred prisoners to potential places of abuse.

The documents have had the most impact inside Iraq, where Prime Minister Nuri al-Maliki has come under renewed pressure as he seeks a second term following hard-fought elections.

The US image worldwide took a severe blow in 2004 when images emerged of US troops humiliating inmates at Abu Ghraib prison. US military courts have found 11 soldiers guilty, handing them sentences of up to 10 years in prison.

US President Barack Obama opposed the Iraq invasion and has declared an end to the US combat mission. But his administration fought the release of the WikiLeaks documents, saying they could pose risks to US forces and their assets in Afghanistan and Iraq.

A military task force sifting through the documents has determined that WikiLeaks removed the names of the more than 300 individuals who would have been at risk, Pentagon spokesman Colonel Dave Lapan said.

"However, information remains in the documents posted that could lead to the identification of those individuals," such as their titles or positions, Lapan said.

WikiLeaks earlier faced criticism not only from the Pentagon but also from some human rights advocates, who called it irresponsible not to filter the raw information.

WikiLeaks spokesman Kristinn Hrafnsson told the BBC that suggestions the website had an anti-American agenda were "totally wrong."

"A lot of people supporting WikiLeaks are very fond of the basic principles and ideals that are the basis of American society," he said, mentioning the Constitution's First Amendment which strictly safeguards freedom of speech.

But in China, which often faces criticism for denying freedoms to its citizens, state media said the WikiLeaks documents tarnished the credibility of the United States.

"The magnitude of the crimes should make every righteous person angry. It again puts a big question mark against the US self-proclaimed image as the world human rights champion," the China Daily said in a commentary.