Reuters news agency said four planes dropped bombs on a house early on Thursday morning, killing the two leaders and 17 other people.
One of those killed is believed to be Aden Hashi Eyrow, whose house was bombed.
The leaders were members of al-Shabaab, the military wing of the Union of Islamic Courts.
The bombing took place in the central Somali town of Dusamareb, 300km north of Mogadishu, the capital.
Mukhtar Robow Adumansur, a senior commander of the Union of Islamic Courts, told Reuters: "It is true that infidel planes bombed Dusamareb.
"Two of our important people, including Aden Hashi Eyrow, were killed in the incident."
The Union of Islamic Courts ruled Somalia briefly until their ousting at the end of 2006.
Al-Shabaab has fought against the Somalian government and its Ethiopian allies since early 2007.
The US military has repeatedly attacked targets in Somalia over the past year.
Last Mod: 02 Mayıs 2008, 11:13