(Updates with details of fresh attack)

BAGHDAD, July 14 (Reuters) - A car bomb killed at least seven people in central Baghdad on Saturday, police said, hours after a blast flattened an apartment building, killing one person.

Police said 15 people were wounded by the bomb in a car parked near a petrol station in Karrada, a busy Shi'ite neighbourhood in the heart of the capital.

The casualties were among people queuing to get fuel and nearby shoppers, police said.

U.S. and Iraqi security forces have launched a major clampdown in the hope of stemming sectarian bloodshed between minority Sunni and majority Shi'ite Arabs, but violence continues to erupt.

Another car bomb earlier reduced an apartment building to rubble in a Shi'ite district of southern Baghdad.

Police said one person was killed and four others were wounded when a parked minivan filled with explosives blew up next to the residential building.

Residents helped clear debris as firefighters doused fierce flames from burning cars. Two crutches lay close to small pools of blood near a damaged car.

The number of big car bombs has fallen in Baghdad in recent weeks as U.S. and Iraqi security forces step up operations against militant groups behind car bomb factories around the city. But deadly attacks remain frequent.

AlertNet news is provided by