Baghdad, Iraq ? Iraq’s interim prime minister publicly blamed U.S.-led forces Tuesday for “gross negligence” that led to the massacre of as many as 51 American-trained Iraqi soldiers as insurgents carried out new attacks against Iraqi police and national guardsmen and assassinated a local government official.

In remarks to the Iraqi National Council, Prime Minister Iyad Allawi said of Saturday’s killings: “This was a horrible crime. … We think that this is due to negligence by the multinational forces.”

Allawi offered no explanation of how his allies had been negligent. He said the Iraqi government would investigate the incident and report back to him within three weeks.

A U.S. military spokesman focused the blame on the insurgents.

“This was a coldblooded and systematic massacre by terrorists. They, and no one else, must be held fully accountable for these heinous acts,” Lt. Col. Steven Boylan said in a statement. “We will provide full support and cooperation to establish the facts and avoid repetition of similar incidents.”

Allawi’s comments were a rare public criticism of American-led forces by the former exile who was once linked to the CIA. The prime minister has found a firm ally in President Bush and reciprocated last month with an impassioned defense of U.S. involvement in his country during a speech before Congress.

Iraqi security forces have suffered a rapidly rising death toll in recent months. Although the U.S. military has delivered substantially more equipment to them in that time, some Iraqi officials complain that police, national guard and army personnel lack sufficient training, equipment and protection from insurgent attacks.

Speaking to the National Council on Tuesday, Iraqi Interior Minister Falah Naqib said it would take more than six months to train police well enough to combat “terrorists.”

Since late June, when the interim government was appointed, there have been 92 suicide car bombings that killed 567 people in Iraq, Naqib said, according to news services.

“The Iraqi police are not trained to combat terrorism,” Naqib said. “The Iraqi police are trained to capture criminals and robbers. … We cannot solve these problems in a day and night. We cannot reach a good result in a month or two or three or six. We need time.”

In the weekend attack, the soldiers, who had just graduated from training at a large military base in eastern Iraq, were ambushed as they were traveling home on leave. Insurgents, wearing police or national guard uniforms, set up a checkpoint and stopped the minibuses in which the unarmed soldiers were traveling.

Most of the soldiers were found lying face down in rows, shot in the back of the head. Others were found on a burned bus in the same area. Almost all the victims were from southern Iraq.

A similarly chilling incident appeared to be under way Tuesday, as an Arabic Web site run by a militant group calling itself the Ansar al Sunna Army announced that the group had captured 11 members of the Iraqi national guard between Baghdad and the south-central city of Hillah. The site showed photographs of the guardsman. Most were young and looked plaintively at the camera.

The group claimed responsibility over the weekend for the beheading of an Iraqi who worked for the U.S. military near the northern city of Mosul. A video posted on the Web site showed the killing in horrific detail.

In other violence Tuesday, a roadside explosive hit a police convoy in Baqubah, and a second group of police were struck by another blast when they came to the convoy’s rescue. One police officer was killed, and seven officers and two civilians were injured.

Just 15 minutes later, a city council member from the Baqubah area, who was on his way to a meeting, was killed when three unidentified assassins armed with machine guns attacked his car. One of his bodyguards died as well.

In Fallujah, a U.S. airstrike on an alleged safe house killed a high-ranking associate of Jordanian-born militant Abu Musab al-Zarqawi the military said. The United States has been bombing sites in the rebel stronghold since midsummer in an effort to kill him and eliminate his group.