Mogadishu - At least 15 people are dead after a suicide car bomber posing as a milk delivery van detonated at a district headquarters in Somalia's capital, police said on Tuesday.The death toll may rise, as some were badly hurt in the explosion at Wadajir district headquarters in Mogadishu, Captain Mohamed Hussein told The Associated Press.Most of the dead were civilians, Hussein said. Aamin Ambulance service said it had transported 18 wounded, seven of them women. Two of the eight bodies it transported were women, it said.The al-Qaeda-linked al-Shabaab extremist group quickly claimed responsibility for the attack via its Shahada News Agency, according to the SITE Intelligence Group, which monitors jihadist groups.At the blast scene, debris was burning and bricks and body parts were scattered among destroyed cars. One man was pulled alive from under a large stone after a wall fell on him in the explosion.Weeping women stood nearby, anxiously waiting for news about loved ones.The blast comes less than a week after al-Shabaab gunmen carried out an overnight siege on a popular restaurant in the Somali capital, killing at least 31 people.The Somalia-based al-Shabaab often targets high-profile areas of Mogadishu, including hotels, military checkpoints and areas near the presidential palace. It has vowed to step up attacks after the recently elected government launched a new military offensive against it.Al-Shabaab last year became the deadliest Islamic extremist group in Africa, with more than 4 200 people killed in 2016, according to the Washington-based Africa Center for Strategic Studies.The extremist group also faces a new military push from the United States after President Donald Trump approved expanded operations, including airstrikes, against al-Shabaab.