Nuri al-Maliki said on Tuesday that "there is a limit to the acceptable excuses".
"Yes a mistake may happen but there is an acceptable limit to mistakes," al-Maliki said, when asked about a US investigation into the deaths of 24 Iraqis in the western town last November.
"We are worried about the increase in 'mistakes'. I am not saying that they are intentional. But it is worrying for us," he added.
"We emphasise that our forces, that multinational forces, will respect human rights, the rights of the Iraqi citizen," al-Maliki told the BBC through an interpreter.
"It is not justifiable that a family is killed because someone is fighting terrorists. We have to be more specific and more careful."
In Washington, the White House pledged on Tuesday that the public would be told everything learned during a defence department investigation into the events in Haditha.
The killings there have led US commentators to make comparisons with the March 16, 1968, killing of unarmed civilians by US troops in the Vietnamese village of My Lai.
Twenty-four Iraqis were killed in
the military operation in Haditha
Tony Snow, the White House spokesman, said the defence department was investigating the incident and that he had been assured that "when this comes out, all the details will be made available to the public, so we'll have a picture of what happened".
The three officers who have been relieved of command from the marine battalion involved are not targets of investigations, Paul Hackett, a lawyer for one of officers said on Tuesday.
Instead, about a dozen enlisted marines - the highest ranking among them a staff sergeant - are being investigated, Hackett said.
Al-Maliki said his own government would probe not just Haditha but other cases: "We will ask for answers not only about Haditha but about any operation ... in which killing happened by mistake and we will hold those who did it responsible."
Noting a probe into the deaths of people in a US-Iraqi raid on a Baghdad mosque in March, he added: "We will use our authority since we are responsible for protecting the Iraqi people, and we are elected by people... Those who kill intentionally or through negligence should be tried."