A prominent U.S.-based human rights group says it disagrees with some coalition leaders who are justifying the invasion of Iraq as a humanitarian intervention.

Human Rights Watch laid out it position in 407-page World Report on human rights and armed conflict, released at a London news conference on Monday.

In the keynote essay, the New York-based group's executive director, Kenneth Roth, said the Iraq invasion ended one of the world's most brutal government.

However, Mr. Roth said United States President George Bush and British Prime Minister Tony Blair should not justify the war as a humanitarian intervention.

Mr. Roth argued that such interventions should be reserved for stopping imminent or ongoing slaughter. For example, Mr. Roth says an invasion of Iraq would have been justified in 1988 to stop Saddam Hussein's large-scale killing of ethnic-Kurds.

Mr. Roth told the news conference American and British officials have turned to a humanitarian justification for the war because no weapons of mass destruction have been found.

"At this stage, the dominant justification for the war, the alleged presence of weapons of mass destruction, seems to be fading away," he said. "Increasingly, the only way to justify this war is as a humanitarian one. And I don't think that justification works."

As for the conduct of the war, Mr. Roth says careful planning of bombing targets helped prevent civilian casualties. However, he says there is evidence that coalition troops sometimes use excessive force in pursuing anti-coalition militants, and he says those abuses are not being vigorously investigated and punished.

He also had harsh words for the tactics of the militants.

"We are deeply concerned with the methods being used by the insurgents, which have been both indiscriminate with large-scale loss of civilian life, and have been against inappropriate targets," added Mr. Mr. Roth. "That is to say, people who are cooperating with coalition authorities but who are not in the military chain of command or coalition military."

As for the future, Mr. Roth says he fears Iraq may experience communal violence in the next few months. He says the northern oil city of Kirkuk is a particularly dangerous potential point of conflict, with displaced Kurds demanding their land back from Arab families moved there during the Saddam Hussein regime.