A series of bombs struck U.S. and Iraqi security forces in Baghdad and the northern city of Mosul on Monday, killing at least 32 people and wounding dozens, Iraqi officials said.

The bloody attacks were a grim reminder of the dangers facing Iraqis as they try to take over their own security. The Iraqi parliament last week approved a security pact with the United States that would let the Americans stay in Iraq for three more years to help maintain security.

At least 16 people were killed and 46 wounded in a nearly simultaneous double bombing near a police academy in eastern Baghdad.

A homicide attacker detonated his explosives vest packed with ball-bearings at an entrance to the academy, then a car bomb exploded about 150 yards away, apparently aimed at those responding to the initial blast, the U.S. military said.

The blasts occurred within minutes of each other on Palestine Street, according to police and witnesses.

One 22-year-old recruit who was injured in the attack said he had been standing in line with other applicants when the blasts occurred.

"We came today for appointment at the academy and I learned later that some of my friends were killed in the second explosion," Ali Nasir said. "It seems that there is no security and terrorism will not end."

Bloodied police uniforms and a military boot left by victims were scattered with the crumpled metal hulk of the car bomb on the charred street in the aftermath of the bombing, according to Associated Press Television News footage.

The attacker apparently was a teenage boy whose severed head was taken to a local hospital, a police officer said. An AP photographer saw the head and confirmed it appeared to be of a teenage boy.

Those killed included five policemen and 11 recruits, while the wounded included 11 policemen and 35 recruits, according to police and hospital officials who spoke on condition of anonymity because they weren't authorized to release the information.

The Iraqi military spokesman Maj. Gen. Qassim al-Moussawi's office said 11 people were killed and 34 wounded, while the U.S. military put the initial casualty toll at six killed and 20 wounded.

In the northern city of Mosul, a homicide car bomber detonated his explosives as a joint U.S.-Iraqi convoy drove by in a crowded commercial area, a police officer said. The officer also declined to be identified for the same reason.

Mohammed al-Nuaimi, a 30-year-old employee of a nearby tire store, said local businessmen had received verbal warnings that the explosion would occur so they should evacuate the area.

"We started to close our shops and people were trying to flee when a U.S.-Iraqi convoy passed. One minute later, a big explosion took place and I was thrown to the ground and lost consciousness," he said in a telephone interview from his hospital bed.

At least 15 people — most civilians — were killed and 30 wounded in that attack, the officer said. An official at the morgue where the bodies were taken confirmed the death toll.

The U.S. military said initial reports show eight Iraqi civilians were killed in Monday's attack. It says two U.S. soldiers and 30 Iraqis were wounded.

Conflicting casualty tolls are common in the chaotic aftermath of bombings in Iraq.

Earlier Monday, a senior Defense Ministry official was wounded in a roadside bomb attack that killed one of his bodyguards, according to al-Moussawi.

The blast occurred in the Sulaikh neighborhood, a mainly Sunni area in northern Baghdad.

The wounded official, Maj. Gen. Mudhir al-Mola, is in charge of affairs related to the Sunni guards known as Sons of Iraq who have joined forces with U.S. troops against Al Qaeda in Iraq, according to al-Moussawi.

The move is considered a key factor in the overall decline in Iraq violence.

The Shiite-led government assumed responsibility for the Sunnis in Baghdad this fall.