ISAHAQI, Iraq — U.S. forces bombed a house during a raid north of Baghdad early today, killing 11 people — mostly women and children, while insurgent attacks elsewhere left four dead, police and relatives said.

The U.S. military acknowledged the raid and said it captured one insurgent. It took place near Balad, about 50 miles north of the capital. But the military said only four people were killed — a man, two women and a child.

Authorities in the Shiite holy city of Karabala, meanwhile, imposed a six-day driving ban starting Thursday to protect pilgrims from a wave of sectarian killing.

Defense Secretary Donald Rumsfeld hinted that U.S. troop levels may increase slightly in the coming days because of the pilgrimages connected to the holiday of Ashura, which ends March 20. Increased attacks marked the celebration during 2004 and 2005.

Rumsfeld said Gen. George Casey, the top U.S. military officer in Iraq, "may decide he wants to bulk up slightly for the pilgrimage." He did not elaborate.

Police Capt. Laith Mohammed, in nearby Samarra, said American warplanes and armor were used in the strike, which flattened the house and killed the 11 people inside.

An AP reporter at the scene in the rural Isahaqi area said the roof of the house collapsed, three cars were destroyed and two cows killed.

Eleven bodies, wrapped in blankets, were driven in the back of three pickup trucks to the Tikrit General Hospital, about 45 miles to the north, relatives said.

Associated Press photographs showed the bodies of two men, five children and four other covered figures arriving at the hospital accompanied by grief-stricken relatives. The victims were covered in dust with bits of rubble in their hair.

Riyadh Majid, who identified himself as the nephew of the killed head of the family — Faez Khalaf — told AP at the hospital that U.S. forces landed in helicopters and raided the home early today.

Khalaf's brother, Ahmed, said nine of the victims were family members who lived at the house and two were visitors.

"The killed family was not part of the resistance, they were women and children," Ahmed Khalaf said. "The Americans have promised us a better life, but we get only death."

The U.S. military said it was targeting and captured an individual suspected of supporting foreign fighters for the al-Qaida in Iraq terror network.

"Troops were engaged by enemy fire as they approached the building," said Tech. Sgt. Stacy Simon, a military spokeswoman. "Coalition forces returned fire utilizing both air and ground assets."

Bomb blasts killed at least four more people and injured dozens today in Baghdad and north of the capital.

The worst attacks were in Baqouba, 35 miles northeast of Baghdad, where there were at least three explosions.

A suicide bomber on a bicycle missed a police patrol, killing two civilians and injuring six others, police said. The provincial command said the bomber's explosives appeared to have detonated prematurely as he was pedaling toward the patrol.

Later, an explosion in a cell phone shop killed two more people and injured 12, police said.

Police at the scene found apparatus used to detonate explosives, leading them to suspect the shop may have been used to manufacture bombs. At least five other shops were damaged in the blast.

Another bomb targeting a police patrol injured two officers, police said.

The Iraqi army hit back today, arresting about 20 suspects and confiscating numerous weapons in a dawn raid in a nearby farming area, said Lt. Col. Tarik Muhei.