MOGADISHU - Unknown assailant shot dead a lawmaker in the Somali transitional federal parliament in the capital Mogadishu on Wednesday, official and eyewitness said.

The masked attackers who were armed with pistols shot the Somali Member of Parliament Aden Bulleh Mohamed near his home in the western district of Mogadishu, police office Ali Hussein told Xinhua.

The assailants suspected of belonging to the radical Islamist group of Al-Shabaab managed to escape the scene of the attack after shooting the lawmaker in the head several times.

"The two men wearing masks approached the official and started shooting him in the head and fled after he fell down on the ground, " said eyewitness Mohamed Harun, who was at the scene during the shooting.

Although no group has so far claimed responsibility for the killing it is members of Al-Shabaab who have often carried out such prominent assassinations of key Somali government officials.

Somali government officials said they were investigating the attack and will apprehend those behind the assault on the lawmaker and will be brought before the courts of law.

Meanwhile sporadic attacks against Somali government soldiers and African Union (AU) peacekeepers in Mogadishu have been carried out by suspected insurgents using hand grenades thrown at bases of the government troops and AU peacekeepers.

A number of government soldiers and civilians were injured in the attacks that have been taking places since Al-Shabaab were forced out of Mogadishu in August saying they withdrew from the capital to change tactics from conventional war to guerilla fighting of "hit and run" method.

The Al-Shabaab is facing another assault from allied Kenyan and Somali government forces at the southern border provinces following a wave of raids by alleged Al-Shabaab fighters inside Kenya to abduct foreign tourists and aid workers.