U.S. soldiers shot and killed at least seven Iraqi women and children at a checkpoint in southern Iraq in an episode that reflected the military's nervousness over the danger of suicide attacks.

The U.S. military said the soldiers opened fire Monday when the driver of the van failed to stop as ordered.

A Washingon Post reporter at the scene said 10 Iraqis in all were killed, including five young children. In the first moments after the shooting, an Army captain accused soldiers of not having fired warning shots quickly enough.

The soldiers were from the Army's 3rd Infantry Division, which lost four soldiers Saturday at another checkpoint when an Iraqi soldier posing as a taxi driver detonated a car bomb in a suicide attack.

Elsewhere, the Central Command said, an Iraqi prisoner was shot to death after he reached for a Marine's weapon while being questioned.

And Central Command said another Iraqi was killed Tuesday in a similar incident, at a checkpoint near the south-central town of Shatra.

Monday's checkpoint shooting occurred along Route 9 near Najaf, about 20 miles north of the site of Saturday's suicide bombing.

Central Command said initial reports indicated the soldiers followed the rules of engagement to protect themselves.

"In light of recent terrorist attacks by the Iraqi regime, the soldiers exercised considerable restraint to avoid the unnecessary loss of life," the statement said.

Navy Capt. Frank Thorp, a U.S. Central Command spokesman in Doha, blamed the deaths on the Iraqi regime's guerrilla tactics and its practice of using women and children as shields.

"The most horrendous thing about this is that this is the result of what is apparently the strategy of the regime to challenge us at checkpoints, which has caused us to be on our toes and ensure that these are not suicide bombers," he said. "So the blood of this incident is on the regime of Saddam Hussein."

The shooting is likely to stoke opposition to the U.S.-led invasion among Iraqis in the Shiite Muslim region, where Washington had hoped for a popular uprising against Saddam and his Sunni Muslim regime. Instead, U.S. forces have faced stubborn resistance by Saddam's forces in Najaf and other southern Shiite strongholds.

According to an account by the Central Command, the van approached the Army checkpoint Monday afternoon. Soldiers motioned for the driver to stop but were ignored. They then fired warning shots but the vehicle kept moving toward the checkpoint. Troops then shot into its engine. As a last resort, the military said, soldiers fired into the passenger compartment.

Two other civilians were wounded, according to the U.S. military, which said it is investigating the incident.

"They tried to warn the vehicle to stop; it did not stop," Marine Gen. Peter Pace said on PBS. "And it was unusual that that vehicle would be full of only women and that the driver was a woman. So we need to find out why it was that they were acting the way they did."

The military statement said 13 women and children were in the van. But The Washington Post, whose reporter is with the 3rd Infantry, said 15 people were in the vehicle and 10 were killed, including five children who appeared to be under 5. One of the wounded was a man not expected to live, the Post reported on its Web site.

The newspaper described the vehicle as a four-wheel-drive Toyota crammed with the Iraqis' personal belongings.

In its description of the shooting, the Post quoted a 3rd Infantry Division captain as saying the checkpoint crew did not fire warning shots quickly enough.

The Post described the captain watching through binoculars and ordering the soldiers by radio to fire a warning shot first and then shoot a machine-gun round into the vehicle's radiator. When the vehicle kept coming, the captain ordered, "Stop him!"

About a dozen shots of 25 mm cannon fire were heard from one or more of the platoon's Bradley fighting vehicles, the Post said.

The captain then shouted over the radio at the platoon leader, "You just ÛexpletiveÝ killed a family because you didn't fire a warning shot soon enough!" according to the Post.

"It was the most horrible thing I've ever seen, and I hope I never see it again," Sgt. Mario Manzano, 26, a medic, told the Post.

U.S. medics evacuated survivors of the shooting, according to the Post. A woman who had superficial head wounds was flown by helicopter to a U.S. field hospital when it was learned she was pregnant, the Post said.

U.S. officials offered the victims an unspecified amount of money to compensate them.