Updated

The U.S. military says it has conducted an airstrike that killed four al-Shabab extremists after "partner forces came under small arms fire."

The U.S. Africa Command says Sunday's airstrike was carried out near the community of Araara in Lower Juba region in the south.

The statement says no U.S. service members were on the ground during the Somali-led operation and that according to its assessment no civilians were injured or killed in the airstrike.

The U.S. military has carried out more than two dozen airstrikes, including drone strikes, this year against the al-Qaida-linked al-Shabab, the deadliest Islamic extremist group in sub-Saharan Africa.

Somalia on Sunday marked the first anniversary of al-Shabab's deadliest attack, a truck bombing in the capital, Mogadishu, that killed well over 500 people.