Police said insurgents first killed the shop owner in front of his store in a popular market area in the Shula district of northwestern Baghdad and then detonated a bomb at the door of the shop when people crowded around the body.

The attack bore the hallmark of Sunni Islamist insurgents such as Al-Qaeda, who often target crowded, mostly Shiite areas.

Overall violence has declined sharply in Iraq in the last two years but a March 7 parliamentary election that produced no clear winner has fueled tensions again.

Gunmen and bombers killed about 125 people on Monday in series of attacks across the country that included assaults on security checkpoints in Baghdad and car bombings in the southern oil hub of Basra and the southern town of Hilla.

The attacks appeared to be aimed at showing Iraqis that insurgents still were strong enough to mount coordinated attacks nationwide despite recent setbacks inflicted by US and Iraqi forces, including the death of Abu Ayyub Al-Masri, the leader of Al-Qaeda in Iraq, in a raid.

Late on Tuesday, a roadside bomb killed five Iraqi police officers and wounded 14 others who were lured to a Baghdad market by the detonation of another improvised explosive.