BAGHDAD, Iraq (AP) – Iraqi troops backed by U.S. jets raided a Shiite stronghold in the capital Friday, killing and wounding dozens of people in a crackdown on militias blamed for much of Iraq’s worsening sectarian violence.

At least 17 others died in a wave of bombings and mortar attacks against mostly Sunni mosques in the Baghdad area and northern Iraq. A Sunni cleric was also kidnapped in the capital, a Sunni official said.

The raid began before dawn in Sadr City, a Shiite district of east Baghdad, as Iraqi troops backed by the Americans swooped down on a building where an undisclosed “insurgent leader” was holed up, a U.S. statement said.

Gunmen opened fire from the roof with automatic weapons and rocket-propelled grenades, triggering a firefight in which an estimated 30 to 40 “enemy fighters” were killed, the U.S. said. There were no American or Iraqi government casualties, the statement added.

The insurgent leader was captured, U.S. spokesman Maj. Gen. William Caldwell said. He would not identify him, but said he and his followers have kidnapped, tortured and murdered Iraqi citizens and had tried to smuggle weapons from Syria.

Residents of Sadr City said they believed the raid targeted Abu Diraa, a commander of a breakaway faction of the Mahdi militia, led by radical cleric Muqtada al-Sadr. Several residents insisted Abu Diraa had escaped but offered no proof.

Prime Minister Nouri al-Maliki, a Shiite, has promised to disband sectarian militias, blamed for the tit-for-tat killings that have heightened tensions between Shiites and Sunnis and raised fears of civil war.

But the raid enraged many of the 2.5 million Shiites in Sadr City as rumors spread through the crowded slum district that most of the dead were civilians killed as they slept on their rooftops.

Many Iraqis sleep on roofs during the sweltering summer months because the electricity crisis means they don’t have fans and air conditioning.

An al-Sadr aide, Sheik Abdul-Hadi al-Darraji, said 11 civilians were killed and dozens wounded.

“This is a big escalation from the American side,” he said. “I condemn all the silence toward such violations and I call for the withdrawal of the American forces.”

Lt. Kadim Abbas Hamza of the Sadr City police said nine people, including a woman, were killed and 14 were wounded. He also said eight people were arrested. A hospital official said seven people were killed and 34 wounded.

Caldwell said the operation was planned and directed by Iraqis with U.S. troops in a supporting role. However, an Iraqi army officer said the Americans gave them a list of people to be arrested in advance of the raid.

Caldwell said U.S. jets fired three precision weapons during the 45-minute battle and that U.S. troops manning a security cordon took fire from “multiple positions.”

The raid occurred a day after U.S. and Iraqi troops arrested a top regional commander of the Mahdi militia near the southern city of Hillah, a U.S. statement said. Adnan al-Unaybi was commander of Mahdi militiamen in the Euphrates valley south of the capital, the statement said.

Both moves appeared to signal a crackdown on Shiite militiamen. Shiite gunmen are believed to be holding Sunni parliament member Tayseer al-Mashhadani, who was seized in a Shiite neighborhood nearly a week ago.

In another sign of sectarian tensions, a series of bombs and a mortar blast struck four Sunni mosques in the Baghdad area and a Shiite mosque in the northern city of Sinjar, killing a total of 17 people and wounding more than 50, police said.

After sundown Friday, five mortar shells exploded on a Shiite neighborhood in western Baghdad, killing three people and wounding 40, according to police Lt. Mohammed Khayoun.

The attacks occurred on the main Muslim day of worship and followed a suicide car bombing Thursday that killed 12 people, mostly Iranian pilgrims, at a Shiite shrine in the southern city of Kufa.

During a Friday sermon, a leading Sunni official said a Sunni cleric had been abducted Friday in the capital. The official, Ahmed Abdul Ghafour al-Samaraie, said 181 Sunni preachers had been killed since Saddam Hussein’s ouster in April 2003 and called on the government to disband Shiite militias.

Al-Samaraie accused police and Mahdi militiamen of killing a Sunni cleric at a checkpoint south of Baghdad. He did not say when the alleged killing occurred.

“After killing him, they started to dance and wave his turban in the air,” al-Samaraie said, “We are fed up with these mean people. Either these people will be punished by the government or we will be forced to defend ourselves.”

Also Friday, Japan began withdrawing its 600-member military contingent from Iraq. The first group of about 30 soldiers left their garrison in Samawah and flew to Kuwait, Japanese media said. Their departure marked the beginning of the end of Japan’s biggest overseas military mission since World War II.

The rest of the troops are expected to leave within the next two weeks, although Japanese officials have announced no timetable for security reasons. Prime Minister Junichiro Koizumi sent the troops to Iraq in early 2004 for a humanitarian mission.

Security in Samawah and the rest of Muthanna province is handled by British and Australian forces. However, they are due to hand over responsibility to the Iraqis this month.