Two bombs have exploded in the Somali capital of Mogadishu close to the presidential palace and parliamentary buildings.
A suicide car bomb exploded outside the gate of a popular hotel while a second blast was heard shortly after near the former parliament house which had military personnel inside.
Police said more than 20 people, including government officials, are thought to be trapped inside the hotel where security forces are trying to end a siege by al-Shabab extremists.
The Nasa-Hablod hotel, which is located 600 metres from the presidential palace, is known to be frequented by politicians and members of Mogadishu's elite.
At least 18 people are reported to have died in the blasts.
Police officer Ali Nur told Reuters most of those killed were policemen who were stationed close to the hotel's gate. A former lawmaker is also reported to have died.
"Security forces have entered a small portion of the hotel building.... the exchange of gunfire is hellish," he said.
Captain Mohamed Hussein told the Associated Press that more than 30 people have wounded in the attack and gunfire could be heard inside the hotel where fighting is still raging.
The al-Shabab extremist group has claimed responsibility for the attack and said its fighters were still inside the hotel.
Abdiasis Abu Musab, the group's military operations spokesman, told Reuters: "We targeted ministers and security officials who were inside the hotel. We are fighting inside."
Police said the death toll is likely to rise.
Major Abdullahi Aden told Reuters the hotel was "a busy hotel frequented by lawmakers, (military) forces and civilians".
A huge cloud of smoke was seen above the scene after the explosions and one Reuters witness described a dozen wrecked cars and bloodstains in front of the hotel.
Somali police officer Nur Mohamed said: “The second car bomb occurred at the ex-parliament house where there were [military] forces."
Police said a third blast had been heard at the scene of the attack outside the hotel.
Captain Hussein told AP that an attacker detonated a suicide vest.
The attack in Somalia's capital comes two weeks after more than 350 people were killed in a massive truck bombing on a busy Mogadishu street in the country's worst-ever attack.
The extremist group al-Shabab often targets high-profile areas of Mogadishu.
Since the blast two weeks ago, President Mohamed Abdullahi Mohamed has been visiting regional countries to seek more support for the fight against the extremist group.
A 22,000-strong multinational African Union force in Somalia is expected to withdraw its forces and hand over the country's security to the Somali military by the end of 2020.
The US military also has stepped up military efforts against al-Shabab this year in Somalia, carrying out nearly 20 drone strikes.
Additional reporting by agencies.
