Information Minister Mohamed Abdi Hayir told state radio that a meeting of security officials was under way inside one of the hotels, the SYL, at the time of blast and that one minister and some state radio journalists were injured in the attack.
The hotel is frequented by government officials and police said it believed the facility was the likely target.
The SYL and another hospitality facility, both located near the Presidential Palace, were partially destroyed by the blast, Major Mohamed Ali, a police officer, told Reuters.
"The blast killed 10 (people) including soldiers and civilians and 30 others were wounded," Ali said.
Gunfire could be heard after the blast and a huge cloud of smoke rose above the palace, outside which were the remnants of the car and splattered blood, according to a Reuters witness.
Al Shabaab's Radio Andaluz said the group was behind the attack and their military operations spokesman, Sheikh Abdiasis Abu Musab, said the attack had killed 15 soldiers and "injured many others including a lawmaker". Seeking to impose its own harsh form of Islam, al Shabaab, wants to topple the Western backed government in Mogadishu and also push out the 22,000-strong African Union mandated AMISOM peace keeping force backing it.
The group was pushed out of Mogadishu by AMISOM in 2011 but have remained a serious threat, launching frequent attacks aimed at overthrowing the government.
The militants have claimed responsibility for several explosions in Mogadishu, including a car bomb and gun attack last week at a popular beach restaurant in the capital that killed 10 people.
In a separate incident, al Shabaab fighters attacked military bases housing government and African Union troops south west of the capital Mogadishu late on Monday, police and the group said on Tuesday.
Military officer Major Bile Farah said a soldier and two al Shabaab fighters were killed in the attack in K-50 and Muri in Lower Shabelle region.
Abu Musab told Reuters the group's fighters had killed 10 soldiers and commandeered a vehicle from the Somali government soldiers in the Monday attack.