Relations between the British Army and the residents had steadily decayed since the first appearance of troops in August 1969 . In September , after clashes between nationalist and unionist crowds that led to the death of a Protestant man , William King , the British Army erected a ' peace ring ' to enclose the nationalist population in the area they had previously controlled . Roads into the city centre were closed at night and people were prevented from walking on certain streets . Although some moderate nationalists accepted this as necessary , there was anger among young people . Clashes between youths and troops became more frequent . The riot following the Officials ' Easter parade in March 1970 marked the first time that the army used ' snatch squads ' , who rushed into the Bogside wielding batons to make arrests . The snatch squads soon became a common feature of army arrest operations . There was also a belief that they were arresting people at random , sometimes days after the alleged offence , and based on the identification of people that they had seen from a considerable distance . The rioters were condemned as hooligans by moderates , who saw the riots as hampering attempts to resolve the situation . The Labour radicals and Official republicans , still working together , tried to turn the youth away from rioting and create socialist organizations — one such organization was named the Young Hooligans Association — but to no avail . The Provisionals , while disapproving of riots , viewed them as the inevitable consequence of British occupation . This philosophy was more attractive to rioters , and some of them joined the Provisional IRA . The deaths of two leading Provisionals in a premature explosion in June 1970 resulted in young militants becoming more prominent in the organization . Nevertheless , up to July 1971 the Provisional IRA remained numerically small .