Iraq will launch its own investigation into reports that U.S. Marines last year intentionally killed as many as 24 unarmed civilians in the town of Haditha.  U.S. military leaders are ordering mandatory training on legal, moral, and ethical battlefield standards.

U.S. commanders in Iraq say the training will emphasize professional military values and the importance of disciplined conduct in combat.

President Bush says he is troubled by the allegations against U.S. forces in Haditha and believes the additional training will remind troops about what it means to adhere to rules of engagement.

"Our troops have been trained on core values throughout their training, but obviously there was an incident that took place in Iraq that is now being investigated, and this is just a reminder for troops either in Iraq or throughout our military that there are high standards expected of them and that there are strong rules of engagement," he said.

President Bush says there will be a full and complete investigation into what happened in Haditha last November, when news reports say Marines opened fire on civilians after a member of their squad was killed by a roadside bomb.

"The United States of America has got a willingness to deal with issues like this in an upfront way, in an open way and correct problems," he said. "And that is what you are going to see unfold."

President Bush says if there is evidence of wrong-doing on the part of U.S. troops, those responsible will be held to account.

The New York Times reports that the ongoing military investigation contradicts Marine claims that 15 civilians were killed by a roadside bomb and in an ensuing gun battle with insurgents.

Iraqi Prime Minister Nouri al-Maliki has denounced the alleged killings and says the government in Baghdad will launch its own investigation.

At a news conference following a cabinet meeting, the prime minister called for talks with coalition forces about their rules of engagement in Iraq.