MOGADISHU, Somalia — A car bomb exploded Tuesday at a military checkpoint near Somalia’s presidential palace in the capital, killing at least six people, the spokesman for Mogadishu’s mayor said.

The dead included a soldier and five civilians, Abdifitah Halane said. Another dozen people were injured.

The explosive was detonated after soldiers tried to stop the car and the bomber tried to speed through the checkpoint, police Captain Mohamed Hussein said.

The checkpoint is one of several that motorists must go through before reaching the heavily guarded presidential palace, which has seen previous attacks by the Al Qaeda-linked extremist group Al Shabab.

The group later claimed responsibility for the blast via its radio arm, Andalus.

The blast came a few hours after Somalia’s new prime minister unveiled a 26-member Cabinet, the latest step as the fragile central government tries to further assert itself beyond the capital.

The threat of Al Shabab attacks is a major challenge for the country’s new Somali-American president, Mohamed Abdullahi Mohamed, who has vowed to make security a priority in this Horn of Africa nation.

But the extremist group, which was kicked out of Mogadishu under Mohamed’s brief term as prime minister in 2010-2011, has denounced the new president as an ‘‘apostate’’ and warned Somalis against supporting him.

Al Shabab has lost most of its key strongholds across Somalia but continues to carry out deadly attacks.

Associated Press