A Somali government official said a suicide bomber has killed three guards at a government military base in the capital.
Deputy regional governor Abdifitah Ibrahim Shawey said the suicide bomber was white. Authorities believe he was one of around 300 foreigners fighting alongside Islamist insurgents.
He says the bomber tried to enter the base but the three guards refused to allow him access. They were killed when the bomber blew up his car on Sunday morning.
The attack follows two weeks of intensified fighting after two insurgent forces formed an alliance and tried to push the government from the capital.