MOGADISHU, June 20 -- At least 15 people were killed and scores of others injured in a bomb explosion that hit the Wadajir district headquarters in the Somali capital Mogadishu on Tuesday.

Internal Security Ministry spokesman Ahmed Mohamed Mohamud said a vehicle loaded with explosives exploded inside the headquarters and also destroyed houses nearby.

"There are heavy casualties and the death toll could rise," Mohamud told journalists in Mogadishu.

Among the injured is Wadajir district commissioner who was inside the building at the time of the attack. Ambulances rushed to the scene and carried away the wounded to nearby hospitals for treatment.

An eye witness Guled Isse told Xinhua he saw bodies strewn on the floor minutes after the explosion.

Terror group Al-Shabaab has claimed responsibility for the attack, which happened barely a week after another deadly attack at a restaurant in Mogadishu claimed 29 lives.

Most of the casualties were reported to be civilians who were near the scene at time of the car bomb explosion.

Local residents said the blast has ripped through the compound and sent a tick plume of black smoke into the sky.