|Transitional government forces and Ethiopian soldiers forced the Islamic Courts from Somalia in 2006 [EPA]|
Sheikh Mohamoud Ibrahim Suley of the Islamic Courts Union, which was forced from Somalia by transitional government and Ethiopian forces in late 2006, condemned the attack which killed Aden Hashi Ayro.
Al-Shabaab had been the military of the Islamic Courts while they controlled the capital Mogadishu and much of the south of the country for about six months.
"This attack was cowardly and aggressive. We condemn the international, Arab and Islamic communities' silence," he told Al Jazeera.
"These bombs are making Somalis more united. These people do not need bombs, they need international humanitarian help.
""It is good for America to stop, if America continues what it is doing they will reap the harvest of thecrop they have sown."
The country has been without a fully functioning government since the overthrow of Mohammed Siad Barre in 1991.
Attacks stepped up
In recent months opposition fighters have stepped up their attacks on transitional government forces and their Ethiopian backers.
Ali Musa, a local human rights activist, told Al Jazeera that at least 8,552 people have been killed in fighting since the Islamic Courts Union was forced out of Mogadishu in late 2006.
A coalition of opposition groups, the Alliance for Liberation and Reconstitution of Somalia, said after Thursday's bombing in the town of Dusamareeb that it was considering pulling out of peace talks scheduled for May 10.
AMISOM has been deployed in Somalia since March 2007 and should eventually number about 8,000 troops. It is currently made up of 1,650 Ugandan troops and 850 soldiers from Burundi.
Source: Al Jazeera and agencies