Marines' Iraq conduct scrutinised
US marines in Iraq
US marines have been accused of deliberately killing the civilians
The commander of the US Marine Corps is going to Iraq to reinforce standards of behaviour, after allegations that marines unlawfully killed civilians.
In a statement, Gen Michael Hagee said marines risked becoming "indifferent to the loss of human life".
Earlier, the US military said it was investigating the alleged killing of an Iraqi civilian by marines last month.
Another inquiry is investigating allegations that marines killed at least 15 Iraqi civilians last year.
The victims, in Haditha, included women and children.
Officials are probing whether US troops deliberately killed the civilians after a roadside bomb attack on their unit.
Testing war
"Many of our Marines have been involved in life or death combat or have witnessed the loss of their fellow Marines, and the effects of these events can be numbing," said Gen Hagee.
"There is the risk of becoming indifferent to the loss of a human life, as well as bringing dishonour upon ourselves," he said.
DEATH IN HADITHA
November 2005: Initial US military report
One US marine killed in roadside bomb, two injured
Explosion also kills 15 Iraqi civilians
Eight insurgents killed in fire-fight following blast
January 2005: US military preliminary investigation
One US marine killed in roadside bomb, two injured
Fifteen civilians accidentally killed by US fire amid battle with insurgents
March 2006: US military begins criminal investigation
Secrecy over civilian deaths
The war in Iraq, he said, "will continue to challenge us in the commitment to our core values", but it was also testing "our commitment to our belief in the rule of law".
"We must regulate force and violence, we only damage property that must be damaged, and we protect the non-combatants we find on the battlefield," Gen Hagee added.
Residents in Haditha have described how US troops went on a violent rampage after the roadside bomb attack killed a marine while on a routine patrol last November.
At least seven women and three children are thought to have been among those killed.
A growing outcry over the incident prompted US authorities to send military investigators to Haditha to investigate the reports.
They will decide if the civilians died in crossfire or were targeted deliberately in a potential war crime.
The US news magazine Time, which highlighted the case, suggested there was evidence US troops had entered Iraqi homes and shot dead some of those inside.
Wednesday's announcement of the second incident involved the killing of an Iraqi civilian west of Baghdad on 26 April. No further details are available.
