Nine people, most of them members of Somalia's security forces, were killed in a suspected suicide bombing at a checkpoint in the capital Mogadishu on Tuesday, police and witnesses said.

The attack took place near a checkpoint frequented by the security forces, police officer Mohamed Ali said.

"There are still investigations going on but with all indications so far, a suicide bomber caused the blast," he said, adding that six members of the security forces and three civilians were killed and 11 others wounded.

The bombing was claimed the by Al-Qaeda linked Al-Shabaab Islamist group, which has been fighting to topple Somalia's federal government since 2007 and has carried out waves of attacks.

The jihadist group controlled the capital until 2011 when it was pushed out by African Union troops, but it still holds territory in the countryside and launches frequent attacks against government and civilian targets in Mogadishu and elsewhere.