The bomb, late on a hot summer evening, came two days after suspected al Qaeda insurgents launched a series of attacks across the country that killed more than 125 people in what officials described as a message that although the group had been weakened, it was still a threat.

It also came amid continued political wrangling following a March 7 election that produced no outright winner.

A cross-party alliance heavily supported by minority Sunnis took a slim, two-seat lead in the parliamentary vote, but the main Shi'ite-led alliances, including Prime Minister Nuri al-Maliki's bloc, have agreed to join forces to try to form a coalition government.

If they succeed, it could anger the once-dominant Sunnis who supported the Iraqiya party’s list drawn up by former Prime Minister Iyad Allawi, a secular Shi'ite, and could possibly fuel renewed bloodshed as US troops prepare for a sharp reduction in numbers by August.

Earlier the same day, a bomb planted inside a grocery in another mainly Shi'ite area of Baghdad killed three people and wounded 23 others.

Police reports indicate that the insurgents first killed the shops 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 attacks bore the hallmark of Sunni Islamist insurgents such as al Qaeda, who often target crowded, mostly Shi'ite areas.

Gunmen and bombers killed about 125 people on May 10 in a series of random attacks across the country that included assaults on security checkpoints in Baghdad and car and suicide bombings in the southern oil hub of Basra and the southern town of Hilla.