Attackers have reportedly stormed a hotel in the Somali capital of Mogadishu, after setting off a suicide car bomb outside the building.
Government ministers are believed to have been in the hotel when it was attacked.
Local police captain Farah Abdullahi told Reuters: "We hear gunshots inside. I am afraid the attackers have also gone inside the hotel.
"It is too early to know about casualties."
The United States conducted an air strike in Somalia today, targeting a senior al-Shabaab leader, the country's defence department said.
The US is still assessing the results of the strike and said there was no immediate sign of civilian casualties.
Somali Islamist militant group al Shabaab attacked the main African Union (AU) peacekeeping base in the capital Mogadishu on Thursday, the group's military spokesman said.
A Reuters photographer near the base said sporadic gunfire could be heard from inside the compound. African Union officials could not be reached for comment.
"Our fighters have entered AU's Halane base by force through the gate and now fighting is going on inside the base," Sheikh Abdiasis Abu Musab, al Shabaab's military operation spokesman, told Reuters.
At least six people are dead after a blast in the Somali capital Mogadishu, police have said.
The suspected bomb was in a vehicle parked near a popular hotel on a main thoroughfare running through the city.
Sheikh Abii Ubeyda Ahmad Omar has been named as Somalian militant group Al-Shabaab's new leader.
The terror organisation made the decision at a meeting today following the killing of Ahmed Godane by US airstrikes.
Somalian militant group Al-Shabaab has confirmed the death of its leader Ahmed Godane following US aerial bombardment.
One of the major issue discussed at the NATO meeting was the threat from Islamic State. President Obama vowed to 'degrade and ultimately defeat the militants'. His comments came as the Pentagon confirmed it had killed the leader of the Al Qaeda group - Al Shabaab - in a drone strike in Somalia.
ITV News Washington correspondent Robert Moore reports on the President's pledge to deal with the Islamic militants.
The British Foreign Office says the death of Al-Shabaab leader Ahmed Abdi Godane may have "seriously reduced" the group's capabilites and taken Somalia a step closer to peace.
His death means there is more of an opportunity to build enduring peace and stability in Somalia and to work with the people of the region who want nothing more than an end to fighting and bloodshed.
Experts have suggested there is no obvious successor to Godane as al-Shabab leader, raising the prospect that the group's capabilities could be seriously reduced.