Al Shabaab militants say they carried out a suicide bomb attack on a hotel in Somali capital Mogadishu that has reportedly killed up to 20 people, including some members of parliament, and injured many more.

Two explosions and gunfire were heard at the Central Hotel, which is frequented by politicians and businessmen, reports the BBC.

Police earlier told Reuters news agency that six people had been killed.

The BBC put the death toll nearer 20, citing witnesses.

The Somalian deputy prime minister and transport minister were wounded, and militant group Al-Shabaab has claimed responsibility for the strike, reports the agency.

"First the car bomb exploded at the gate of the hotel, then a suicide bomber blew himself up in the hotel compound," police Major Nur Mohamed told the agency.

"There were ministers and legislators inside the hotel. I have seen many people with injuries, including a lawmaker," he said from the scene of the blast.

Al Jazeera correspondent Mohammed Adow tweeted that the attackers had targeted a popular mosque in the hotel where hundreds were performing Friday prayers, with government ministers believed to be among the casualties.

Al-Shabaab, an al Qaeda linked extremist organisation, holds swaths of Somalian countryside, and is battling the UN backed government for control of the country.