A taxi driver at the scene told AFP he saw four bodies being carried away, while another witness called Yusuf Moalim said a senior police official appeared to be among the victims, whose auto had been near the hotel entrance when the blast occurred.
One senior police official and a former MP are among the dead.
A police commander and a former MP are among the dead, following a suicide auto bombs detonating as it rammed into the gate of a hotel close to the capital city's presidential palace.
The al-Shabab extremist group has claimed responsibility for the attack and confirmed that its fighters were inside the hotel.
The first explosion was reportedly caused by a auto bomb.
Residents said there was a huge smoke billowing from the scene after a huge explosion followed with gunfire was heard outside the hotel.
"The Mujahedeen fighters are inside Nasa Hablod 2 hotel where... apostate officials are staying", said a brief statement posted on a pro-Shabaab website, quoting Andalus.
He suffered small injuries on his shoulder and skull from flying glass.
Witnesses said gunmen are fighting inside.
Security officials said Saturday's bomber had pretended his truck had broken down outside the gate.
Farmajo was scheduled to meet the presidents of the Somalia's five federal republics at the hotel later in the evening, he said.
It has not commented on the massive attack two weeks ago; experts have said the death toll was so high that the group hesitated to further anger Somali citizens as its pursues its insurgency.
Al-Shabab has been involved in 987 of 1,827 attacks by militant Islamist groups in Africa this year, according to the Africa Center for Security Studies in Washington, D.C. The Somali group has had a long affiliation with al-Qaeda but now appears to be cooperating with ISIS, controlling much of the countryside, analysts said.
A multinational African Union force with 22,000 troops in Somalia is expected to withdraw by the end of 2020. US military officials and others in recent months have expressed concern that Somali forces are not yet ready.
The US has been actively involving in trying to combat the group, launching 20 drone strikes.