U.S. Turns Up Pressure on Shiite Cleric's Militia

Troops Reach Centers of 2 Holy Cities After Fighting Day-Long Street Battles

BAGHDAD, May 12 -- U.S. forces, using tanks, armored personnel carriers and attack helicopters, pushed into the centers of two holy cities Wednesday in pursuit of bands of masked guerrillas loyal to a rebellious cleric at the heart of the Shiite insurgency.

In Karbala, U.S.-led forces worked with Iraqi police officers to seize a suspected weapons stockpile of the Mahdi Army, the militia loyal to Moqtada Sadr, a 31-year-old Shiite cleric who has emerged as a chief nemesis of the U.S. occupation. Troops came under rifle and mortar fire before dawn, U.S. officials said, setting off day-long street battles involving tanks, Bradley Fighting Vehicles and helicopters.

After dark, in the city of Najaf farther south, U.S. forces attacked militia positions not far from the shrine of Ali, one of Shiite Islam's most sacred mosques. Insurgents took refuge in Najaf's vast and sand-covered cemetery, the most coveted burial site for Shiite Muslims. U.S. officials said the fighters hid behind tombs and staged rocket-propelled grenade and mortar attacks from the sanctuary.

The combat marked an escalation in the U.S. drive to put down the Sadr rebellion, which has swept across southern Iraq and parts of the capital that had welcomed the U.S. invasion that ousted President Saddam Hussein last year. The Mahdi Army has employed guerrilla tactics and has used sensitive holy sites as cover from U.S. attacks.

The strategy has complicated the U.S. effort to contain the Shiite insurgency before handing over limited authority to an interim Iraqi government on June 30. U.S. officials claim the insurgency enjoys little popular support apart from the forces loyal to Sadr, which number in the thousands.

During the morning raid in Karbala, 60 miles south of Baghdad, U.S. military officials said troops discovered rocket-propelled grenade launchers, mortar rounds and explosive devices for roadside bombings inside a warehouse complex and in the neighboring Mukhaiyam Mosque.

The site is roughly 500 yards from the shrines of Hussein and Abbas, second only to the Najaf mosque in terms of religious importance to Shiites. Twenty-two insurgents were killed in the day-long fighting and six U.S. soldiers were wounded, U.S. officials said. They said troops were proceeding with caution inside the city's alleyways and narrow streets to avoid damaging the holy sites.

Witnesses said Sadr militants tried to storm the shrines early in the afternoon but were repelled by armed guards inside the mosques and U.S. Army snipers positioned on rooftops nearby.

"They allowed no one inside" the mosques, said Saad Hussein, 26, who works in a grocery store. "There was shooting back and forth between both sides, but they succeeded in keeping them out."

In the Baghdad slum of Sadr City, U.S. troops clashed in the morning with fighters loyal to Sadr who wielded rocket-propelled grenade launchers. U.S. officials said six insurgents were killed in the sprawling slum, which is named for Sadr's father, Grand Ayatollah Mohammed Sadiq Sadr, who was assassinated by suspected agents of Hussein's government in 1999.

In central Iraq, a series of hit-and-run attacks targeted U.S. military installations and those cooperating with the U.S. occupation. A mortar attack on a U.S. Army base near Balad killed four Filipino contractors, while in Baqubah, a bomb exploded outside the house of an officer with the U.S.-trained Iraqi police force. The explosion killed three members of his family. In the city of Samarra, also inside the area known as the Sunni Triangle, 20 armed men attacked the police station, drove off the officers inside and bombed the building, witnesses said.

[The military on Thursday reported that one U.S. soldier was killed and another was injured on Wednesday when a bomb exploded beside their convoy in Baghdad, the Associated Press reported.]

Reaction to the disclosures of torture in Abu Ghraib prison continued to complicate the U.S. effort to calm the country. At a news conference in Najaf, Sadr used the scandal as a rallying cry, calling on the American public to "pay attention to what your army is committing against our detainees."

As part of a step-by-step campaign to apply pressure on Sadr, U.S. commanders have avoided full-scale assaults on Kufa, which abuts Najaf, and especially on Najaf itself, the site of two major Shiite shrines. Instead, the commanders are trying to weaken Sadr's militia and isolate him, while pressing Shiite leaders to resolve the standoff.