On 21 July 1920, rioting broke out in Belfast, starting in the shipyards and spreading to residential areas. The violence was partly in response to the IRA killing of a northern RIC police officer Gerald Smyth, in Cork, and also because of competition over jobs due to the high unemployment rates. Protestant Loyalists marched on the Harland and Wolff shipyards in Belfast and forced over 11,000 Catholic and left-wing Protestant workers from their jobs. The sectarian rioting that followed resulted in about 20 deaths in just three days. Both Catholics and Protestants were expelled from their homes by the other side, sometimes by fire. The further IRA assassination of an RIC Detective Swanzy in nearby Lisburn on 22 August prompted another round of clashes, in which 33 people died in 10 days. The year 1921 saw three major flare ups in Belfast. Just before the truce that formally ended the Irish War of Independence, Belfast suffered a day of violence known at the time as 'Belfast's Bloody Sunday'. An IRA ambush of an armoured police truck on Raglan Street killed one RIC man, injured two more and destroyed their armoured car. This sparked ferocious fighting in west Belfast on the following day, Sunday 10 July, in which 16 civilians (eleven Catholics and five Protestants) lost their lives and 161 houses were destroyed. Gun battles raged all day along the sectarian 'boundary' between the Falls and Shankill Roads; rival gunmen used rifles, machine guns and hand grenades. Four more would die over the following two days The second spike in violence happened from 29 August to 1 September, in which twenty people were killed. The third eruption was in November, when more than thirty died in response to the IRA bombing city trams taking Protestant workers to the shipyards, killing seven people.