BAGHDAD, (Reuters):

Three car bombs killed 24 people and wounded scores in Baghdad yesterday, and gunmen attacked two Sunni areas, clashing with residents and setting houses on fire.

The violence came on a day when the military command centre that will oversee a planned offensive by Iraqi and United States troops in the city was due to become operational. U.S. officers said on Sunday that the crackdown would begin "soon thereafter".

In the worst blast yesterday, a car bomb targeting a petrol station in the religiously mixed southern neighbourhood of Saidiya killed 10 people and wounded 62, while eight people were killed and 40 wounded when a car bomb exploded in a garage.

A car bomb exploded near a childrens' hospital in Andalus square in central Baghdad, killing six and wounding nine.

The city is on edge as war-weary residents look for signs the security sweep promised by Shi'ite Prime Minister Nuri al- Maliki in January has begun. A U.S. general on Sunday urged Iraqis to be patient and allow for a troop buildup.

The only unusual activity yesterday appeared to be in the southern Dora neighbourhood, where a convoy of 12 U.S. Humvees and four Abrams tanks were seen heading towards Baghdad, but it was not immediately clear if it was related to the planned push.

Police said militants attacked Adhamiya district in northern Baghdad, clashing with residents. There were no immediate reports of casualties, but 15 people were killed there in a mortar barrage on Sunday.