The U.S. military ordered coalition troops in Iraq to undergo special training in ethics and "the values that separate us from our enemies" in the wake of allegations that Marines killed two dozen unarmed civilians in Haditha.

A U.S. Marine stands guard outside a house while the rest of his squad searches for weapons during an operation in the town of Ramadi, in this military handout photo released on September 28, 2005. Al Qaeda militants have gained ground in Ramadi and the 1,500 extra U.S. troops brought to Iraq to help fight them will be used to try to break their grip on the town, the military said on Thursday. [Reuters]

The order came Thursday as Iraq's government launched its own investigation of the deaths last November in the western town as well as other incidents involving U.S. troops. Prime Minister Nouri al-Maliki called the killings "a horrible crime," his strongest public comments on the incident since his government was sworn in May 20.

"This is a phenomenon that has become common among many of the multinational forces," al-Maliki said. "No respect for citizens, smashing civilian cars and killing on a suspicion or a hunch. It's unacceptable."

Al-Maliki's remarks appeared to lend credibility to complaints by Iraqis of what they see as U.S. troops' cultural insensitivity and disregard for Iraqi lives. To many Iraqis, the soldiers are occupiers seeking to control the country's oil wealth.

The Americans, on the other hand, are under intense pressure, isolated from Iraqis by cultural and language barriers and battling insurgents who easily blend into the civilian population. Some of the troops are in Iraq on their third combat tour since the U.S. invasion three years ago.

The training, which will include slideshows, will cover all coalition soldiers in Iraq and last 30 days. Of the 150,000-strong multinational contingent in Iraq, 130,000 are Americans.

"As military professionals, it is important that we take time to reflect on the values that separate us from our enemies," Lt. Gen. Peter Chiarelli, the No. 2 U.S. general in Iraq, said in a statement. "The challenge for us is to make sure the actions of a few do not tarnish the good work of the many."

Maj. Gen. William Caldwell, spokesman for the Multinational Force-Iraq, told a Baghdad news briefing that the training was designed to reinforce what troops learned before coming to Iraq. It will focus on "values and looking at the legal, moral and ethical standards that every one of us in uniform here, as guests of the Iraqi government, need to adhere to," he said.

"The coalition does not and will not tolerate any unethical or criminal behavior. All allegations of such activity will be fully investigated," he said.

Chiarelli's announcement followed last week's visit to Iraq by U.S. Marine Commandant, Gen. Michael W. Hagee, who cautioned troops on the danger of becoming "indifferent to the loss of a human life."

The U.S. military is conducting at least two investigations into the killings of civilians, including women and children, in Haditha on November 19.

The killings followed the death that day of a Marine in a bomb explosion that targeted a military convoy. U.S. Congressman John Murtha, a decorated war veteran who has been briefed by military officials, has said the Marines, angered by the loss of a comrade, shot and killed civilians in a taxi near the scene and went into nearby homes and shot others.

U.S. military investigators have evidence that points toward unprovoked murders by the Marines, a senior defense official said last week. The Washington Post reported Thursday that the investigators will conclude some officers gave false testimony to their superiors, who then failed to scrutinize the reports adequately.

It took nearly a month for U.S. President George W. Bush to be told of the Haditha investigation, the White House said Thursday. Earlier this week, Bush aides had said the president was briefed "soon after" the probe began.

The decision to launch an Iraqi inquiry was made at a Cabinet meeting Thursday, according to Adnan al-Kazimi, an adviser to the prime minister.

A committee of security experts as well as officials from the Justice and Human Rights ministries will look into the Haditha incident as well as other cases where misconduct by U.S. troops is suspected, al-Kazimi told The Associated Press.

An Iraqi government statement said the Haditha "tragedy" violated the guidelines of justice and human rights" and demanded no leniency be shown to its perpetrators.

"The Council of Ministers demands that generous financial compensations be paid to the victims' families and an official apology be presented to the Iraqi government after the results of the investigation are announced," the statement said. It emphasized, however, the need for coordination between the Iraqi side and the U.S.-led coalition forces.

Prime Minister al-Maliki's tone was even tougher.

"It appears to be a horrible crime," he told reporters. "A large number of women, men and children have been killed because of an explosion that targeted a vehicle of the multinational forces."

He said the list of human rights breaches by coalition forces in Iraq was long.

Reinforcing "core values" training could help prevent such alleged incidents, experts said.

"I think it's a healthy thing," said Howard Prince, director of the Center for Ethical Leadership at the University of Texas at Austin. "It's time to step back and do refresher training to remind those how the United States wages war."

However, Prince, a retired Army general, cautioned that training needs to be constantly reinforced. "I think it'll have an effect, but the effect won't be as powerful if it's not sustained by continuous efforts on part of leadership at every level," he said.

Associated Press Writers Antonio Castaneda, Kim Gamel and Patrick Quinn contributed to this report.