A U.S. military strike has killed approximately 30 Islamist al-Shabab militants near the central Somali town of Galcad, where Somalia's military was engaged in heavy fighting, U.S. Africa Command said in a statement.

The operation, which the U.S. military described as a "collective self-defense strike," occurred Friday about 162 miles (260 km) north of the capital Mogadishu, where Somali national forces were under attack by more than 100 al-Shabab fighters, the statement said.

U.S. Africa Command, the military arm of the American government's presence on the continent, said no civilians were injured or killed in the strike. It said three vehicles were destroyed.

Al-Shabab fighters had stormed a Somali military base in Galcad Friday and killed at least seven soldiers, according to the Somali government and the militant group. The fighters exploded car bombs and fired weapons but were eventually repelled.

Somalia's Information Ministry said in a statement that in addition to al-Shabab killing seven soldiers, their soldiers had killed 100 of the group's fighters and destroyed five gun-mounted pickup vehicles known as ‘technicals’.

Al-Shabab has been fighting since 2006 to topple the country's central government and install its own rule, based on a strict interpretation of Islam.

Friday's attack underscored the formidable threat that al-Shabab poses for Somalia's military, despite government successes against the al-Qaida-allied militants last year.