WASHINGTON - The Pentagon says U.S. military forces have targeted the Islamic extremist al-Shabab network in an operation in Somalia.

Pentagon spokesman Rear Adm. John Kirby says the U.S. is looking at the results and will provide more information when appropriate. No further details were available.

Monday's action comes after Somali government forces regained control of a high security prison in the capital that was attacked Sunday by seven heavily armed suspected Islamic militants who attempted to free other extremists held there. The Pentagon statement did not indicate whether the U.S. action was related to the prison attack.

Somali officials say all attackers, three government soldiers and two civilians were killed. The Mogadishu prison is an interrogation centre for Somalia's intelligence agency, and many suspected militants are believed to be held there.