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 . Other examples include the bombing of the Abercorn Restaurant bombing in Belfast in 1972 , where two people were killed and 130 wounded
Bloody Friday
Bloody Friday (1972)
Provisional IRA Belfast Brigade