A U.S. helicopter opened fire on a group of men as they were planting roadside bombs in a Sunni stronghold north of Baghdad on Tuesday, then chased them into a nearby house, killing 11 Iraqis, including five women and one child, the military said.

The airstrikes came a day after Osama bin Laden scolded his al-Qaida followers and other insurgents, saying they have been "lax" for failing to overcome fanatical tribal loyalties and unite in the fight against U.S. troops.

The message of his new audiotape reflected the growing disarray among Iraq's Sunni Arab insurgents and bin Laden's client group in the country, both of which are facing heavy U.S. military pressure and an uprising among Sunni tribesmen.

The men were seen placing the bombs near the volatile northern city of Samarra, said Maj. Peggy Kageleiry, a military spokeswoman.

An Apache helicopter "engaged these enemy forces, and the enemy forces ran into a house and took over the structure," she said, adding the attack aircraft continued to fire at the suspected militants as they tried to escape.

A known member of a roadside bomb-making network was among five military-age men who were killed, but the dead also included five women and one child, the military said in a statement that cited local nationals as its source. The statement said the circumstances surrounding the airstrikes were under review.

Kageleiry had said eight military aged men were among those killed but later revised the figure to five and said an investigation was under way.

She expressed regret for the civilian deaths but blamed insurgents for endangering their lives by running into the house to escape attack by the U.S. forces.

Police and witnesses said 14 people were killed, including four women and eight children.

Dhurgham Hamid, a man from the area that was hit, said the dead included a man who was a supervisor at the provincial education directorate, and his wife, an accountant at the agency.

"They were peaceful people who had nothing to do with the resistance or gunmen," Hamid said.

It was the third claim of civilian casualties from U.S. airstrikes in as many days, raids that have prompted complaints that too many ordinary Iraqis are losing their lives, particularly as the Americans increasingly rely on air power to attack militants.

On Monday, relatives and police said a 42-year-old woman and her 4-year-old daughter were seriously wounded when attack helicopters opened fire before dawn on a duplex that housed a family in one half and a store selling motor oil in the other in Baghdad's Shiite enclave of Sadr City.

The U.S. military said attack helicopters killed one extremists and wounded five after they were seen trying to place a roadside bomb.

Ground forces also called for air support after encountering fierce resistance in a raid targeting a suspected Iranian-linked leader of a kidnapping ring in Sadr City on Sunday, although casualty tolls conflicted. The Americans said 49 militants were killed, but Iraqi officials insisted the number of casualties was 15 — all civilians.

Aides to radical Shiite cleric Muqtada al-Sadr condemned the raid but urged followers to abide by his orders to refrain from violence despite what it called "the crimes of the Americans."

"We call upon al-Sadr's people to show self-restraint. Their reaction should be peaceful and should not violate the order ... to freeze their activities," said Falah al-Obeidi at the cleric's Sadr City office.

Al-Sadr later issued his own statement urging his Mahdi Army militia not to harm or kill fellow Iraqis. He also appeared to call on members of Iraqi government forces to stop cooperating with the U.S. military.

"You army and police of Iraq, don't kill an Iraqi in the name of secular laws or in the name of 'imposing the law,"' he said, using his phrase for the security crackdown in Baghdad and surrounding areas.

The U.S. military has said repeatedly that it welcomed al-Sadr's order to his Mahdi Army fighters but pledged to continue its crackdown against what it says are breakaway factions that are being armed and trained by Iran.

U.S. and Iraqi forces, meanwhile, banned vehicles, motorcycles and bicycles in the streets of the Anbar provincial capital of Ramadi to protect a celebration to commemorate Sheik Abdul-Sattar Abu Risha, the founder of the first anti-al-Qaida group of Sunni tribal leaders who was assassinated by a bomb Sept. 13.

Abdul-Sattar's brother, who has taken over the movement, said it was important to keep pressure on insurgents, recalling that about 50 al-Qaida militants marched through downtown Ramadi a year ago in a show of force.

"The people felt weak and afraid because of al-Qaida. Now there is a feeling of strength," Sheik Ahmed Abu Risha told The Associated Press at his heavily guarded compound as a band practiced for the parade. "This year, I want to have a good parade to show that we support the law."

In other violence Tuesday, a gunfight at a police checkpoint in western Baghdad killed an officer and a gunman, and wounded two officers and three gunmen.