At least six people have been killed and several others injured in a bomb attack carried out in central Somalia, police and residents say.

Major Hussein Osman, a police officer, said the bombing in the central city of Beledweyne on Sunday afternoon rocked a restaurant outside the office of the governor of Hiran region where he was holding a meeting.

Beledweyne is located about 340 kilometers north of the capital Mogadishu.

"A bomber blew up himself in a restaurant," the officer said.

Farah Ali, a local elder, said clan elders were among the dead. "The bomber, who had an explosive jacket, stood inside the restaurant and blew up himself. We were heading to a meeting in the governor’s office when it happened."

Abdiasis Abu Musab, a spokesman for the Takfiri al-Shabab militant group, has claimed responsibility for the assault. "We are behind the attack at the Hiran governor's headquarters. There are casualties. We targeted the workers of the Hiran administration."

The al-Qaeda-linked group has in the past carried out frequent attacks in Mogadishu and other parts of Somalia in a bid to topple the country's government and drive out African Union peacekeeping troops.

Somalia has been at war since 1991, when clan-based warlords overthrew dictator Siad Barre and then turned on each other.

The country has been the scene of deadly clashes between government forces and al-Shabab militants since 2006.

The Takfiri militant group was forced out of the capital by African Union troops in 2011 but still controls parts of the countryside and carries out attacks against government, military and civilian targets. The extremist group is just one of the challenges facing the new Somali government, which is still struggling to expand its authority beyond the capital and other selected areas.