MOGADISHU, Somalia - Police and health officials say at least seven people have been killed and more than 11 others wounded when a vehicle exploded outside a police headquarters in Somalia's capital.

The al-Shabab extremist group has claimed responsibility.

Al-Shabab often targets high-profile areas of Mogadishu, and observers had warned that the al-Qaida-linked group might take advantage of Somalia's current political tensions to strike again.

Somalia's president bowed to growing pressure overnight and announced that he would prepare the country for elections that have been delayed since February.

Anger over his stay in power led to clashes between rival soldiers this week.