A rapid-fire series of explosions in and around Baghdad killed 16 people Sunday, including 10 people who died when a suicide bomber blew himself up in a crowd of police officers, officials said.

In total, at least 10 bombs exploded as Iraqis were headed to work in a reminder of the dangers Iraq still faces despite a drop in violence since the height of the war.

At least nine of the dead were police officers, who often are targeted by insurgents hoping to weaken the security forces as an end-of-the-year deadline for American troops to go home swiftly approaches.

It was the third major attack this month in which security personnel were targeted and took the most losses. Just last week, 27 people were killed outside a police station in the northern city of Kirkuk, and earlier this month 20 police officers in the southern city of Hillah died when a suicide bomber plowed his vehicle into a police compound.

The worst single attack Sunday came near the city of Taji, which is 12 miles (20 kilometers) north of Baghdad.

Police officers had gathered after a roadside bomb targeting a passing American military convoy blew up. When the police arrived on the scene, a suicide bomber walked into the crowd and blew himself up, police and hospital officials said.

Seven police and three civilians died and 19 people, including 15 policemen, were injured, the officials said.

Earlier in the capital, the beginning of the work week was shattered by a quick series of blasts in mostly Shiite neighborhoods.

At about 7 a.m. a car bomb in a parking lot in eastern Baghdad's Sadr City neighborhood exploded, injuring five people and damaging several nearby cars.

"We woke up to a big blast nearby and the glass windows in front of the house were smashed. My young brother was injured by glass," said Namiq Khazal, a 30-year-old who lives in Sadr City about 150 yards (meters) from where one of the blasts went off.

"On my way to the hospital I saw many wounded people and several cars damaged," he added.

Minutes later, also in Sadr City, a bomb hidden in a pile of garbage exploded, killing one person and wounding five more.

Then five minutes later another roadside bomb, this time targeting a police patrol, exploded; 3 policemen and four bystanders were injured in that blast.

In the southwestern neighborhood of Bayaa, the morning calm was shattered by five explosions that went off in rapid succession.

First a roadside bomb targeted a police patrol. Then a minute later another roadside bomb went off in a commercial street followed by two roadside bombs hidden in a pile of garbage on a highway.

Finally, a parked car bomb went off on a road that marks the intersection between Bayaa and the adjoining neighborhood.

In total, five people were killed in Bayaa, including 2 policemen, and 15 people were injured, including six policemen, police and hospital officials said. They did not have a breakdown of where the deaths occurred.

The officials all spoke on condition of anonymity because they were not authorized to speak to the media.

There was no immediate claim of responsibility.

About 46,000 American troops remain in bases around Iraq, and they are slated to leave the country by Dec. 31. But as the deadline approaches, many Iraqis are worried about the ability of their own forces to protect the country from the ever-present threat of bombs and shootings.

In the northern city of Kirkuk, police found on Sunday the dead body of a man believed to be in his late 20s, said the neighborhood police chief, Col. Anwar Qadir. The man's hands were tied behind his back and he was killed execution-style with a bullet to the back of his head.

U.S. officials have long worried that Kirkuk could be a flashpoint for violence especially when American forces who help maintain an uneasy peace in the city and province leave Iraq for good. Three main ethnic groups, the Kurds, Arabs and Turkomen, claim the city as their own, and all would like to control the massive deposits of oil found underneath the city and province.