Officials say militants have set off an explosion outside a United Nations compound in the Somali capital.
Police say the blast occurred Wednesday at a building close to the main U.N. compound near the airport in Mogadishu.
Officials say authorities are engaged in a heavy gun battle with several of the militants. There was no immediate word on casualties.
No one has yet claimed responsibility for the attack. The Somali insurgent group Al-Shabab has claimed repeated attacks in recent days.