A U.S. airstrike on a house in the restive city of Fallujah (search) killed at least 10 people Sunday, hospital and local officials said.

Explosions rocked the city, and angry crowds gathered near the building that was hit.

Several times in recent months, the United States has bombed buildings said to be safehouses used by the network of Abu Musab al-Zarqawi (search), the Jordanian militant blamed for masterminding car bombings and other attacks in Iraq.

Iraq's interim Prime Minister Iyad Allawi has promised more intense cooperation between local leaders and the Americans in rooting out terrorism.

The U.S. military confirmed an airstrike but refused to provide details. It referred all calls to the Iraqi Defense Ministry, which had no comment.

"We heard the sound of jetfighters and then we heard four explosions in the house occupied by civilian residents," said Lt. Saad Khalaf of the Fallujah Brigade (search), a local defense force.

He said that about 10 people were killed inside the house.

"After the explosion, we rushed to the hit house and we started to search for the bodies and we could find remains that were buried later on," Khalaf said.

Marines besieged the city for several weeks last spring and then handed over security to the new Fallujah Brigade, which was made up of residents and commanded by officers from Saddam Hussein's former army. Many of those who fought the Marines joined the brigade.

Allawi issued an unprecedented statement July 5 after the last strike on an al-Zarqawi safehouse, saying his government provided intelligence for its location so the strike could "terminate those terrorists, whose booby-trapped cars and explosive belts have harvested the souls of innocent Iraqis without discrimination, destroying Iraqi schools, hospitals and police stations."