The Somalia-based group has vowed to step up attacks in Mogadishu and elsewhere after the federal government recently announced a new offensive against the group. Targets have included high-profile spots like military facilities, hotels and areas close to the presidential palace.
The car with explosives had been parked outside a restaurant near the city's port, Capt. Mohamed Hussein told The Associated Press. Among the dead were a mother and child who were at the restaurant, he said.
"We would ask Allah to give his mercy on their souls," said Abdifitah Halane, spokesman for Mogadishu's mayor.
Al-Shabab 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.
Somalia's military is under growing pressure to assume more responsibility for the long-chaotic country's security as a 22,000-string multinational African Union force plans to start withdrawing next year.
The prospect of a security vacuum has concerned the international community. Somalia's president has urged that the U.N. arms embargo on his country be lifted soon, saying the military needs more than AK-47s to combat al-Shabab and the small but growing presence of Islamic State-linked fighters in the north.
President Mohamed Abdullahi Mohamed, a Somali-American who was elected in February, has repeatedly said al-Shabab can be defeated within two years, but he warns that could take much longer without a better-equipped national military.
On Tuesday, the national police chief in neighboring Kenya said al-Shabab attacks had increased in that country as the extremist group faces growing pressure from the AU force in Somalia.
Associated Press videographer Mohamed Sheikh Nor contributed.
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