MOGADISHU, May 6 (Xinhua) -- The U.S. army said on Monday evening that it had killed three al-Shabab militants in a precision airstrike in southern Somalia on Sunday.

The U.S. Africa Command (AFRICOM) said in a statement that Sunday's airstrike was in self-defense after al-Shabab fighters attacked Somali forces near Tortoroow.

AFRICOM said the Somali forces were conducting an operation to disrupt the terrorist network in the area and to bolster local support for the government when they came under al-Shabab attack, adding that no civilians were injured or killed.

Sunday's airstrike is the latest in a series of similar missions by the U.S. forces in Somalia in collaboration with Somali and African Union forces in the Horn of Africa country.

The strikes have largely targeted al-Shabab figureheads based in southern Somalia where the group still maintains a strong grip in some regions.