Militants of al Shabaab group stormed police headquarters of Somalia on Saturday after twin bombings wounded at least 17 people nearby in central Mogadishu.
Witnesses saw a heavy exchange of gunfire outside the building, which is also used by police.
Smoke drifted from burning vehicles following a suicide car bombing close to the presidential palace and a second blast near the security building.
The al-Shabab extremist group claimed responsibility for the ongoing attack, reports Reuters.
A spokesman for the Islamist group al Shabaab said it had carried out both bombings and said its fighters remained inside the government security building.
“We stormed the building which houses the security ministry, interior ministry and police,” Abdiasis Abu Musab, al Shabaab’s military operations spokesman, said.
“We are still inside the building,” he said.
Police official Major Mohamed Hussein said the second explosion took place when a vehicle carrying al Shabaab fighters to storm the building after the first explosion was detonated remotely.
“Al Shabaab remotely exploded the second car after they got out of it,” he said, adding that a heavy exchange of fire continued at the occupied building.
In the moments following the blasts ambulance sirens were heard while announcements were made via loudspeaker to help clear the roads.
At least 17 people were wounded in the two bombings, said Abdikadir Abdirahman, director of the Amin Ambulance emergency service.
Somalia has been gripped by violence and lawlessness since the toppling of dictator Mohamed Siad Barre in the early 1990s.