A suicide car bombing has killed at least 11 people and wounded 34 others, including two members of parliament, in the Somali capital, according to police sources.

The armed Islamist movement al-Shabab claimed responsibility for the Wednesday attack in a post on Twitter and said it had killed at least 17 people and wounded 37. The target of the strike was a restaurant apparently frequented by government employees, including high-ranking officials, that has been attacked before.

Al-Shabab said the 17 killed included "senior" members of parliament and intelligence officials, a claim the government denied.

"It is a restaurant where innocent people drink their tea, not a police station," said police spokesman Abdullahi Barise. "I am sure al-Shabab are behind this attack."

Hassan Ali, a police officer, told Reuters the attacker rammed his vehicle into a cafe by the Hotel Muna, which was stormed by al-Shabab fighters in August 2010 in an attack that killed more than 30 people.

Police and a spokesman for African Union troops in Somalia said initial reports showed the attacker first opened fire on people sitting near the hotel before detonating the vehicle.

'Trying to rebuild'

While al-Shabab pulled its forces out of Mogadishu last year, they have launched frequent attacks against the weak, Western-backed Transitional Federal Government with suicide bombers, roadside bombs and grenades.

A truck bomb attack in October that killed more than 70 people was the group's most deadly strike since it launched its campaign in 2007.

Al Jazeera's Nazanine Moshiri, reporting from Nairobi in neighbouring Kenya, said the attacks come at a time when Mogadishu "is trying to rebuild itself after the al-Shabab withdrawal ... but the attack shows al-Shabab is able to get into the city and carry out attacks of this kind".

A one-day conference in London to tackle the instability in Somalia and piracy off its shores is due to be held in two weeks.

Wednesday also marked the day the European Union's new special envoy to the Horn of Africa visited Mogadishu.

William Hague, the British foreign secretary, visited Mogadishu last week and appointed a new ambassador to the country but said Britain would not open an embassy in Mogadishu without improved security.

In another development, Kenyan defence forces said on Wednesday they had killed 13 al-Shabab fighters in southern Somalia.

Among those dead in Afmadow - a city in southern Somalia described by Kenya "as the command centre for al-Shabab forces" - was a senior al-Shabab commander who the forces said could not be named.

Source: Al Jazeera and agencies