Baghdad ? U.S. forces fighting al-Qaida and allied militants intensified operations Wednesday in Baghdad and on all four points of the compass around the capital. To the south, suspected Shiite militiamen bombed three Sunni houses of worship in what may presage a war of the mosques.

Police guard the Khulani mosque in central Baghdad a day after it was targeted by a truck bomber. The death toll from Tuesday's bombing of the Shiite mosque rose to 87 on Wednesday, the Interior Ministry reported. Three Sunni mosques were attacked on Wednesday in apparent retaliation.

An Associated Press reporter in Baqouba, the capital of Diyala province to the north and east of Baghdad, reported intense gunbattles in the streets and around the main market district as American and Iraqi forces sought to clear the city of al-Qaida fighters.

Gen. Abdul-Karim al-Rubaie, an Iraqi military commander in Diyala, told the AP that security forces had ringed the city and were not letting anyone come or go. He said many al-Qaida fighters had hidden their weapons and were trying to flee Baqouba.

“We fear that the insurgents want to mingle with civilians. … Citizens have given us the names of hundreds of al-Qaida elements who have quit fighting and are hiding in their houses in Baqouba. These people are going to be arrested after the end of the battles,” the general said.

The latest military report on the Diyala offensive, which began Monday night, said U.S.-led forces had killed 41 insurgents, discovered five weapons caches and destroyed 25 bombs and five booby-trapped houses.

Forces join fight

The head of a Sunni insurgent group that has turned against al-Qaida in Diyala province and is cooperating with U.S. and Iraqi forces in the area said his fighters were participating in the operations and had succeeded in clearing several neighborhoods in eastern and western Baqouba.

The group leader, who declined to be identified for fear of retribution, spoke as his fighters linked arms, chanted and danced. Women ululated in celebration. An AP reporter also saw residents in the Mustafa area in western Baqouba serving food to the former insurgent fighters. Other residents began repairing their shops.

The U.S. military said it has 10,000 American soldiers in Diyala province, an al-Qaida bastion, a troop strength that matched in size the force that American generals sent against the insurgent-held city of Fallujah 2 1/2 years ago.

With all of the nearly 30,000 additional troops ordered to Iraq by President Bush now in place, the military said the massive operations on Baghdad’s flanks were “a powerful crackdown to defeat extremists” and named the combined offensives “Operation Phantom Thunder.”

In what appeared to be the second largest assault, an estimated 2,500 U.S. soldiers were pushing into districts south and southeast of the capital. They killed four insurgents, detained more than 60 others and destroyed 17 boats, “significantly disrupting insurgent operations on the Tigris River,” the military said.

West of Baghdad, U.S. and Iraqi forces were engaging insurgents and al-Qaida elements in more rural areas, the military said. “These operations are helping to interdict the enemy along the belts between Baghdad, Fallujah, Ramadi and the cities of the Western Euphrates River Valley.”

Attacks on mosques

In a renewed blow to stability Wednesday, suspected Shiite militants blew up three Sunni mosques south of Baghdad, causing heavy damage but no casualties. The bombings were apparently revenge strikes for a suicide truck bombing a day before that badly damaged an important Shiite mosque in the heart of the capital. At least 87 died in that attack.

Police said suspected Shiite militiamen detonated a bomb inside a Sunni mosque in Haswa, 30 miles south of Baghdad, about 1 a.m. About six hours later, militants struck again at a mosque near Hillah, 60 miles south of the capital. A third Sunni mosque was attacked and damaged in an explosion in Iskandariyah, 30 miles south of Baghdad; that mosque was first attacked last week.

The attackers near Hillah also targeted the imam’s house near the mosque, but the cleric fled when he saw them coming, according to the police.

The Sunni mosque bombings appeared to be retribution for Tuesday’s suicide truck bombing against the Shiite Khulani mosque in central Baghdad – the deadliest single attack in Iraq in two months.

At a joint briefing with a U.S. military spokesman, Brig. Qassim al-Moussawi, of the Iraqi army, said the truck was carrying about 50 cooking gas cylinders and about 1,100 pounds of TNT.

Al-Moussawi said the truck bomb was prepared in the nearby Sheik Omar industrial zone and that the Iraqis had no checkpoints on roads between there and the mosque.

Police initially said the bomb was hidden in a truck piled high with electric fans and air conditioners.