NEW : One officer was hurt in a third night of violence in Belfast . NEW : About 150 youths fired shots and threw bombs at officers . NEW : Police are now trying to identify those involved . BELFAST, Northern Ireland (CNN) -- Prime Minister David Cameron denounced `` unacceptable '' violence .
NEW : One officer was hurt in a third night of violence in Belfast . NEW : About 150 youths fired shots and threw bombs at officers . NEW : Police are now trying to identify those involved . NEW : Prime Minister David Cameron denounced `` unacceptable '' violence .