Witnesses say a car bomb has exploded outside a major hotel in Somalia's capital, and that gunmen have stormed the building.

The bomb erupted late Wednesday afternoon outside the Hotel Ambassador in central Mogadishu.  Witnesses tell VOA Somali that security forces cordoned off the area and that soldiers moved into the hotel to flush out the gunmen.

There was no immediate word on casualties.  

The assault came just hours after officials reported an assault elsewhere in Somalia killed the militant commander responsible for last year's massacre at Garissa University College in Kenya.

Mohamed Mohamud, better known as Dulyadeyn, was head of al-Shabab's feared "Amniyat" unit and masterminded the April 2015 attack on the college that left 148 people dead, nearly all of them students.

There are conflicting reports about the circumstances of the militant's death.  A senior Somali official, speaking on condition of anonymity, said U.S. helicopters fired missiles into a car in which Dulyadeyn and two others were traveling.

A security minister in the Jubba region, Abdurashid Janan, told VOA Somali that the militant was killed by a U.S.-trained Somali commando unit known as Danab, or lightning.

The strike took place in the southern town of Bula-Gaduud, about 30 kilometers north of Kismayo. Frightened residents there said they heard the sounds of flighting overnight.