Alaa Al-Marjani, Associated Press
A U.S. soldier stands guard as a Blackhawk helicopter lands in Karbala, where the U.S. military turned over security duties Monday.

BAGHDAD — A suicide bomber rode his bicycle into a crowd of police recruits in Baqouba on Monday, killing at least 29 people in a province that has become a battleground among U.S. forces, al-Qaida militants and Shiite radicals.

A group of Shiite and Sunni clerics, meanwhile, were rescued one day after they were kidnapped in the capital after meeting with the government to discuss how to coordinate efforts against al-Qaida in Iraq.

In a reflection of the extraordinary complexity of Iraq, the U.S. military blamed a Shiite militant for the kidnapping. The military did not reveal its evidence but has said that so-called rogue Shiite groups are doing everything possible to stop Iraqis from joining U.S. forces — even in the fight against the Sunni al-Qaida in Iraq.

Suicide bombings, viewed most often as the work of al-Qaida, have taken a mighty toll among police and army recruits and are carried out to discourage Iraqi men from joining the country's struggling security forces.

Police and hospital officials reported at least 19 people wounded in the attack in Baqouba, the capital of Diyala province 35 miles northeast of Baghdad. Mohammed al-Kirrawi, a doctor at the Baqouba general hospital, said most of the victims were struck by ball bearings packed in the bomber's suicide vest and that the hospital lacked equipment to save many of the wounded.

Akram Salman, a 22-year-old Sunni, said he, too, was among the approximately 60 recruits waiting outside the police station for a day of training.

Salman declared the bombing an inside job because the suicide attacker penetrated heavy security surrounding the police camp without being searched.

He said police failed to stop the bomber when he changed course suddenly from the main road toward the recruits.

"The police are infiltrated. Many people join the police, but they have affiliations with al-Qaida. These infiltrators made it easy for the bomber to attack us," he said. "There are two main checkpoints on the main road leading to the camp. It would be impossible for a man on a bicycle to pass without being properly searched."

The kidnapped tribal sheiks were also from Diyala province. Contradicting original reports, Iraqi Defense Ministry spokesman Mohammed al-Askari said only nine sheiks were kidnapped and that eight were freed. He said four kidnappers were killed and six were wounded in the rescue operation. He did not say who carried out the raid.

Reports on Sunday had said seven Shiites and three Sunnis were kidnapped as they drove out of Baghdad after meeting with the Shiite-dominated government's adviser for tribal affairs.

Police found the bullet-riddled body of one of the Sunni sheiks, Mishaan Hilan, about 50 yards away from where the ambush took place, according to an officer, who spoke on condition of anonymity because he was not authorized to release the information. The sheik was identified through the mobile phone found on his body.

The U.S. accused Shiite militia leader Arkan Hasnawi, a former brigade commander in the Mahdi Army militia, of the kidnapping.

Hasnawi's breakaway Shiite fighters have battled al-Qaida for control in Diyala since the terrorist organization moved into the region and sought to make it a headquarters. Al-Qaida was largely driven out of its stronghold in Iraq's westernmost province, Anbar, after Sunni tribes rose up against the organization's brutal tactics and austere version of Islam. The U.S. military has courted both Sunni and Shiite tribal leaders in Diyala, hoping for a similar outcome.

Three months ago, radical Shiite cleric Muqtada al-Sadr ordered his Mahdi Army fighters to lay down their arms for as long as six months, but thousands of followers dissatisfied with being taken out of the fight have broken off to form their own groups. The U.S. military says the rogue fighters are funded and armed by Iran to foment violence. Iran denies the allegations.

The military said Hasnawi's actions demonstrated that he has violated the cease-fire order and "joined forces with Iranian-supported special groups that are rejecting Muqtada al-Sadr's direction to embrace fellow Iraqis."

The kidnapping and the Baqouba bombing occurred during the first two days of Maj. Gen. Mark Hertling's command in the volatile region north of the capital. His 1st Armored Division took over Sunday from the 25th Infantry Division under the command of Maj. Gen. Benjamin Mixon.

Hertling acknowledged Sunday that violence remained high in the area but expressed confidence that the military has al-Qaida on the run.

A U.S. brigadier general was wounded in a roadside bombing Monday in northern Baghdad, the military reported.

Brig. Gen. Jeffrey Dorko, commanding general of the Gulf Region Division, was the highest-ranking American officer to be hurt since the conflict began in March 2003. Dorko was in stable condition and was evacuated to Landstuhl Regional Medical Center in Germany; his injuries were not life-threatening.