sentences:  In addition to attacks on the Army, a central part of the Belfast Brigade's campaign was the bombing of commercial targets such as shops and businesses.The most devastating example of the Provisionals' commercial bombing campaign was Bloody Friday on 21 July 1972 in Belfast city centre, where 22 bombs were exploded, killing nine people and injuring 130.While most of the IRA's attacks on commercial targets were not designed to cause casualties, on many occasions they killed civilian bystanders.