Attackers hit policemen dismantling an apparent decoy bomb with a live blast Wednesday, killing 12 officers and injuring three others near a northern Iraq city, police said. Police Brig. Sarhat Qadir said the explosion occurred 15 kilometers (10 miles) northwest of Kirkuk as a group of police were trying to cordon off the area. He said officials believed the bomb being dismantled was a decoy to draw in more police before the second bomb exploded. Insurgents also launched a string of attacks in the capital. A car bomb targeting vehicles carrying Iraqi army soldiers hit civilian traffic instead, wounding three passers-by and destroying five cars, witnesses and Iraqi officials said. Almost simultaneously, another car bomb hit a convoy of sports-utility vehicles like those used by many private contractors as it traveled down the deadly stretch of road connecting Baghdad's international airport to the city center, witnesses said. Meanwhile, twin blasts exploded near a convoy of two U.S. Humvees and a fuel tanker as it made its way through an eastern Baghdad neighborhood, witnesses at the scene said. The truck burned violently and sent up a large plume of black smoke visible across Baghdad. It wasn't immediately clear if there were any casualties in the latter two incidents. The U.S. military had no immediate comment.