Reports from the Somali capital, Mogadishu, say Islamist militants have stormed a hotel near the presidential palace.
Gunfire and grenade explosions can be heard from inside the Somali Youth League hotel which is popular with government officials.
"We thought they were police but they started hurling grenades and firing us when they neared and so we exchanged fire at the gate of the hotel," a police officer is quoted by the Reuters news agency as saying.
Many guests are reported to be inside the building.
The jihadist movement al-Shabab says it carried out the attack.
The group carries out regular attacks in Mogadishu and elsewhere in Somalia, often targeting hotels.
In August 2016, it said it was behind a bomb attack on the same hotel which killed 22 people.