Al-Shabab militants have claimed responsibility for what officials are calling a suicide bomb attack on a United Nations compound in the Somali capital.
Police say a suicide bomber set off a powerful explosion outside the offices of the U.N. Development Program near the airport in Mogadishu early Wednesday. Witnesses reported heavy gunfire between militants and police near the facility following the blast.
On its English-language Twitter page, al-Shabab said its fighters had stormed the building and gained "complete control of the compound." Minutes later, the group said its fighters were "still fighting some Western mercenaries."
The African Union's regional peacekeeping mission, AMISOM, said in a Twitter message that its troops were at the compound "within minutes," and have "currently secured" the site. There was no immediate word on casualties.
African Union and Somali forces drove the Islamist extremist group from Mogadishu about two years ago. But the group has continued to carry out periodic, guerilla-style attacks since then.
In its Twitter posting Wednesday, AMISOM condemned the attack, saying such incidents only "derail the efforts of the Somali people to recover from years of lawlessness." But it said that the "cowardly act" will strengthen its commitment to "rid Somalia of the Al-Shabab threat."