Baghdad, Iraq ? In a bloody surprise attack, the U.S. military launched precision weapons into a poor residential neighborhood of Fallujah on Saturday to destroy what officers described as a safe house used by fighters loyal to Abu Musab Zarqawi and perhaps at times by the fugitive terrorist leader himself.

Residents said about 20 people were killed, including women and children, despite a cease-fire with U.S. occupation forces that has kept a relative peace for the last six weeks in the rebellious town 35 miles west of Baghdad. Images from the site of the blast showed two collapsed houses, with people in white robes picking through the rubble looking for buried victims and lost property.

“This leads to nothing but more confrontation with the enemy,” Abdullah Janabi, head of Fallujah’s Mujahiddin Council, declared in an interview with Al Jazeera television.

A statement issued by Brig. Gen. Mark Kimmitt, spokesman for U.S. military forces in Iraq, said it was not known whether the elusive Zarqawi was inside the house at the time of the attack — 9:30 a.m. — but that “multiple confirmations of actionable intelligence” indicated that several of his operatives were present. Kimmitt said 20 minutes of secondary explosions pointed to a large store of munitions and explosives in the targeted building.

Zarqawi, a Jordanian national whom U.S. officials have linked with the al-Qaida network of Osama bin Laden, has been cited by U.S. occupation authorities as one of the leaders of a relentless campaign of bombings and assassinations being waged against the U.S. occupation and Iraqis who cooperate with the U.S.-sponsored Iraqi interim government.

“Wherever and whenever we find elements of the Zarqawi network, we will attack them,” Kimmitt’s statement said.

A senior U.S. military official said he did not dispute the casualty toll given by Fallujah residents, which also spoke of two dozen injured people.

But the official said most of those killed and wounded were inside the two buildings destroyed by the U.S. attack, suggesting they were not bystanders, and Kimmitt’s statement said U.S. planners had decided the high-quality targets were worth the risk of civilian bloodshed.

“This was not an attack on the people of Fallujah, but against a known safe house,” the statement said. “It is standard operating procedure to conduct a detailed collateral damage estimate prior to approval of this type of mission. The collateral damage estimate was within permissible limits, and this operation was within standing rules of engagement.”

Fallujah has been under the control of loosely organized Islamic militiamen since early May. Their authority has been largely unopposed despite the presence of the 1,700-member Fallujah Brigade, a peacekeeping force commanded by former Iraqi army officers in cooperation with Marine forces assigned to the area.

U.S. forces and Fallujah militiamen fought tough, bloody engagements through most of April, after four U.S. contractors were killed, burned and mutilated in the previous month. Several hundred Iraqis were killed in the clashes, which included U.S. airstrikes that also inflicted civilian casualties. Human Rights Watch on Thursday called for an investigation of a confrontation in which the rights group said U.S. troops fired into a crowd of protesters April 28.

The town of 300,000, lying in what is known as the Sunni Triangle because of its predominantly Sunni Muslim population, was long known as a stronghold of former president Saddam Hussein’s Baath Party and a source of tribal support for his rule.

Against that background, Gen. Mohammed Abdullah Mohammed Shehwani, who heads Iraq’s new National Intelligence Service, pressed visiting Deputy Defense Secretary Paul Wolfowitz in a meeting Friday not to renew U.S. attacks on Fallujah. As with Shiite Muslim militiamen in Najaf, 90 miles south of Baghdad, many Iraqi political figures cooperating with the U.S. occupation have urged political solutions rather than armed confrontation with anti-occupation fighters.

But U.S. military officers have been disappointed with the Fallujah Brigade’s lack of control. In particular, they have complained that those responsible for killing and mutilating the U.S. contractors have not been turned over and that foreign fighters have not been arrested and handed to occupation authorities.

U.S. officials have said they believe that foreign terrorists have found refuge in Fallujah, including Zarqawi on occasion, and are helping organize the attacks against U.S. soldiers, particularly car bombs steered to their targets by suicide drivers.

“He’s had a number of locations,” a senior U.S. military official said Saturday in explaining the strike. “This may have been one of the locations where he’s at. … We just don’t have any evidence.”

In addition to the U.S. attack in Fallujah, U.S. troops battled insurgents near Baqubah, 30 miles northeast of Baghdad, for the fourth day, the military official reported. One U.S. soldier and several Iraqis have been killed in the clashes.

Meanwhile, in what appeared to be a new development in the 14-month-old U.S. occupation, about 500 women staged a demonstration against violence in Sadr City, a Shiite Muslim neighborhood in eastern Baghdad that has been the scene of repeated clashes between militiamen and U.S. occupation troops.

Draped in mourning veils, the women marched to the offices of Moqtada Sadr, a young cleric who has been leading the uprising against U.S. troops, and then back again through the streets of their slum.

“The people who pay for the violence are the women,” said Falama Khafaji, a former Governing Council member whose brother was assassinated by insurgents in late May. “We want a stop to the violence, the U.S. to leave the neighborhood and a re-activation of reconstruction projects, like water and sewage.”