MOGADISHU (Reuters) - A car bomb exploded in the center of the Somali capital near the presidential palace on Monday, a blast that appeared to target senior government officials, police and residents said.

It was unclear how many people could have been killed or injured in the suicide attack, police said.

Security in Mogadishu has improved greatly since Islamist rebels allied to al Qaeda fled the city after a military offensive in August 2011, but bombings and assassinations in the coastal city - blamed on militants - still occur often.

(Reporting by Feisal Omar and Abdi Sheikh; Writing by James Macharia; Editing by Louise Ireland)