The Provisional Irish Republican Army ( IRA ) was an Irish nationalist movement founded in December 1969 when several militants , including Seán Mac Stíofáin , broke off from the Official IRA and formed a new organization . Led by Mac Stíofáin in the early 1970s and by a group around Gerry Adams since the late 1970s , the Provisional IRA sought to bring about an all-island Irish state . Between 1969 and 1997 , during a period known as the Troubles , the group conducted an armed campaign , including bombings , gun attacks , assassinations and even a mortar attack on 10 Downing Street . On July 21 , 1972 , in an attack later dubbed Bloody Friday , the group set off twenty-two bombs , killing nine and injuring 130 . On July 28 , 2005 , the Provisional IRA Army Council announced an end to its armed campaign . The IRA is believed to have been a major exporter of arms and to have provided military training to groups such as the FARC in Colombia and the PLO . In the case of the latter there has been a long-standing solidarity movement , as evidenced by many murals around Belfast
Bloody Friday
Bloody Friday (1972)
History of terrorism