MOGADISHU (Reuters) - The number of people killed in twin suicide bomb attacks on two restaurants in Somalia’s southern city of Baidoa has risen to 20 and another 40 people were injured, a local hospital official said on Sunday.

Two suicide bombers blew themselves up in restaurants in Baidoa in the early evening on Saturday. Islamist militant group al Shabaab claimed responsibility for the attack. A spokesman for the group said it had targeted the restaurants because they were frequented by government troops.

The attacks followed a U.S. air strike on Friday against al Shabaab militants in Haradere, a district in Galmudug region. Al Shabaab wants to topple Somalia’s Western-backed central government and impose its own rule based on a strict interpretation of Islamic sharia law.

“We received 20 dead people and about 40 others injured from the twin blasts of yesterday,” Abdifatah Hashi, the general manager of Baidoa city hospital told reporters on Sunday.

On Sunday, a year to the day on which suspected al Shabaab bombings killed more than 500 people in Mogadishu, a Somali military court carried out the execution of a man convicted of being involved in the attacks.

“The Somali military court executed today Hasan Aden Isak who was an al Shabaab member and accused of being behind the October bombing,” the court’s deputy prosecutor Mumin Hussein Abdullahi told state-run Radio Mogadishu.

Al Shabaab never claimed responsibility for the attacks which were the deadliest since the group began its insurgency in 2007.

Somalia has been engulfed by violence and lawlessness since the early 1990s after the toppling of dictator Mohamed Siad Barre.