Iraqi police say at least two people were killed and more than a dozen others wounded in a suicide truck bombing and insurgent gunfire in central Baghdad Wednesday.

Police say the attack occurred near the Agriculture Ministry building and a hotel used by Iraqi police and their foreign instructors.

They say gunmen dressed in police uniforms shot dead a guard at a security checkpoint, while the suicide attacker detonated his explosives-laden garbage truck after driving into the ministry's compound.

Separately, Iraqi police said late Tuesday they found the bodies of 19 people - all wearing civilian clothes and killed execution style - in the town of Qaim, near the Syrian border.

Meanwhile, the U.S. military is accelerating its probe into last week's shooting death of an Italian agent by U.S. forces. The incident occurred Friday, when U.S. troops at a checkpoint near Baghdad airport fired on a car carrying the Italian agent Nicola Calipari and a newly freed Italian hostage, Giuliana Sgrena, a journalist.