A car bomber penetrated the heavily fortified Green Zone in the center of the capital on Tuesday but was stopped by U.S. Marines at a checkpoint before he was able to detonate the vehicle, the military said.
U.S. troops destroyed the explosives-rigged car and detained the bomber, a military spokesman said.
The U.S. military's Baghdad press office offered no details on the incident, and it was not immediately clear how the bomber was able to enter the most secured compound in Iraq, which houses the U.S. Embassy and the Iraqi government. Thousands of Iraqis and foreigners live and work inside the Green Zone.
Meanwhile, officials described the killing Sunday of a reputed high-ranking operative of al Qaeda in Iraq, Abdallah Najim Abdallah Muhammad Juwari, also known as Abu Azzam.
Abu Azzam, whom officials called insurgent leader Abu Musab Zarqawi's top lieutenant and the group's operational commander in Baghdad, was killed Sunday during a raid on a high-rise apartment building in Baghdad, the officials said. He refused to surrender to Iraqi and American troops.
"By taking Abu Azzam off the street, another close associate of Zarqawi, we have dealt another serious blow to Zarqawi's terrorist organization," Maj. Gen. Rick Lynch, a U.S. military spokesman, said in a statement.
Abu Azzam had served as Zarqawi's right-hand man in Anbar province for much of 2004, the U.S. military said, commanding the largest group of foreign fighters involved in the fighting in Fallujah in November. This year he went to Baghdad, where officials said he directed and controlled all terrorist activity in and around the city.
Abu Azzam "was responsible for the planning and execution of countless attacks against Iraqi civilians and security forces as well as multi-national troops, using car bombs and direct violent attacks," said Laith Kubba, a spokesman for Prime Minister Ibrahim Jafari. "He is literally responsible for the death of hundreds of Iraqis."
Also on Tuesday, the military announced that a U.S. Marine was killed by a bomb during combat operations Saturday in the western town of Khalidiyah. The Marine's name was not released.
In Baqubah, about 35 miles north of Baghdad, a suicide bomber wearing an explosive belt blew himself up in a crowd of police recruits, killing at least 10 and wounding 28, police and hospital officials said. Adheed Mutib, a physician at Baqubah General Hospital, said the death toll could increase because most of the wounded were in critical condition.
Ali Khayyam, a press officer at Diyala province's police command, said the bomber targeted recruits of the Iraqi Intervention Force, a special police unit.
At the hospital, Hilmi Kamal, 22, a resident of Baghdad who suffered burns on his legs, said: "We were standing in the queue and there was a man who disobeyed the policeman. When the policeman went away, the man ran toward us and blew up."
In Kirkuk, about 150 miles north of the capital, unknown armed men assassinated Maj. Fakhir Hussein, a police officer with a counterterrorism unit. The attack, at about 9:30 a.m., also wounded another officer, said Maj. Gen. Sherko Shakir, Kirkuk's police chief.
Gunmen also killed one Iraqi soldier and wounded another as they were traveling on the Kirkuk-Tikrit road, said Capt. Firas Obaidi of the Rashad police station in Kirkuk.
In Baghdad, a car bomb exploded near a U.S. military convoy, wounding five Iraqi civilians.
U.S. officials have predicted that bomb attacks would increase with the approach of a national referendum on a new constitution, scheduled for Oct. 15, with areas around the Green Zone particularly vulnerable.
Special correspondents Bassam Sebti in Baghdad and Hassan Shammari in Baqubah contributed to this report.