One soldier was killed and at least six others injured in Somalia on Sunday when a suicide bomber blew himself up at a military base in the west of the capital Mogadishu, a soldier and a hospital worker said.

The suicide bomber had disguised himself as a regular soldier and joined others as they filed into a military base early Sunday before he detonated the explosive, Captain Aden Omar, a soldier at the base said.

“We lost one soldier and several others were injured. The bomber blew up himself at a check point,” he said.

A nurse at Madina Hospital in Mogadishu said they had received one dead soldier and six others who were wounded.

It was not immediately clear who had carried out the attack but Islamist group al Shabaab frequently carries out bombings and gun attacks in Somalia and elsewhere.

The al Qaeda-allied group wants to topple Somalia’s central government and establish its own rule based on its own strict interpretation of Islamic sharia law.