The Pentagon says a U.S. airstrike targeted and killed nine al-Shabab militants in Somalia on Wednesday.

Navy Capt. Jeff Davis, a Pentagon spokesman, says Somali forces who were going after a bomb-making network in the Puntland region came under small arms fire from enemy fighters.

Davis says there were U.S. military advisers with the Somali forces, and the U.S. launched a defensive airstrike to protect them.

He says the military is looking into reports that the people killed in the strike may not have been enemy fighters. He says no U.S. forces were injured.

This is the second airstrike this week that the U.S. carried out against al-Qaida-linked al-Shabab militants in Somalia.