"The explosion hit a hotel in the town and it killed several people, any others were also injured," said Mohamed Abudlahi Moalim, a senior commander with the Ahlu Sunna Wal Jamaa militia, which controls the area.
Witnesses said a man entered a restaurant, where lawmakers were meeting with the public over lunch to discuss the setting up of a regional administration, before blowing himself up.
"The people killed are two lawmakers and four civilians... among the wounded are two other MPs," a witness, Mohamud Ibrahim said.
"They were meeting the civilians to discuss the setup of a local administration," said Hassan Abdulle, a businessman.
No group immediately claimed responsibility for the attack in the Dhusamareb, a strategic town in the central Galgadud region, which was wrested back from Al-Qaeda allied Shebab insurgents by pro-government forces last month.
Ahlu Sunna, an Ethiopia-backed force that follows Somalia`s traditional Sufi branch of Islam, pushed the Shebab out of Dhusamareb in fierce battles in March.
Lawmakers are struggling in efforts to achieve a "roadmap" signed by Somalia`s disparate leaders for the formation of a government by August 20 to replace the weak transitional body in Mogadishu.
Under the agreement, the latest among more than a dozen attempts to resolve the bloody civil war, lawmakers must agree on a system of government for Somalia`s fragmented regional -- and often rival -- administrations.
The deal is opposed by the Shebab, who have vowed to topple the Western-backed government, launching repeated guerrilla attacks. (*)
Editor: Kunto Wibisono
Copyright © ANTARA 2012