BAGHDAD, Iraq (CNN) -- A roadside bomb killed three Iraqi children and injured seven as they gathered around American troops handing out toys on Sunday, police and government officials told CNN.

Three U.S.soldiers were also killed in the explosion in Baquba, north of Baghdad, a police official said.

Other insurgent attacks on Sunday hit a government security convoy and an Iraqi military academy, officials said.

In central Baghdad, a parked car packed with explosives detonated as a government security convoy passed, killing nine people and wounding 20, according to an Interior Ministry official.

Two security officers in the Finance Ministry convoy were among those killed, and four police were among the wounded in the bombing in the Karrada neighborhood, the official said.

Also in the capital, a roadside bomb destroyed a U.S. military vehicle as it traveled in a convoy in the Talbiya neighborhood on the edge of Sadr City, according to the ministry official. There were no reports of casualties.

Another roadside bomb wounded three Iraqi civilians when it struck their car in northern Baghdad's Kasra neighborhood Sunday morning, the official said.

A dozen mortar rounds landed on the Iraqi Military Academy in the Rustamiya area on the outskirts of southern Baghdad Sunday morning, but there were no reports of casualties, the official said. Fifteen minutes later, the U.S. military found and destroyed a vehicle carrying mortar launchers parked in a nearby Shiite area in southeastern Baghdad, the official said.

The U.S. military also destroyed a vehicle loaded with mortar launchers parked in northeastern Baghdad's Qahira neighborhood, 20 minutes after five mortar rounds landed on a joint Iraqi-American security station Sunday morning, the official said. There was no word on casualties.

In the northern city of Mosul, a parked car loaded with explosives detonated near a police patrol Sunday morning, killing three Iraqi civilians and wounding 15 people including five police officers, a Mosul police official said.

An Iraqi police officer trying to defuse a roadside bomb in Tikrit was killed when it detonated, police said. Three other members of the detonation squad were wounded. Tikrit is located in Salaheddin province about 100 miles (160 kilometers) north of Baghdad. E-mail to a friend

CNN's Mohammed Tawfeeq contributed to this report.

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