Cars were set alight and masked people pelted a police van with petrol bombs Saturday, the second straight evening of disorder in pro-British parts of Northern Ireland amid rising post-Brexit tensions in the region.Many pro-British unionists fiercely oppose the new trade barriers introduced between Northern Ireland and the rest of the United Kingdom as part of Britain’s departure from the EU and have warned that their unease could lead to violence.Political leaders, including Britain’s Northern Ireland minister, had appealed for calm earlier Saturday, but police said they were responding to reports of disorder in Newtownabbey on the northern outskirts of Belfast.A video posted on Twitter by the Police Federation for Northern Ireland showed four masked individuals flinging petrol bombs from close range at an armored police van, which they also kicked and punched.Fifteen officers were injured in the Sandy Row area of Belfast on Friday when a small local protest developed into a riot. Police said the rioters attacked them with masonry, metal rods, fireworks and manhole covers.The injuries included burns, head wounds and a broken leg, resulting in the arrest and charging of seven people, two of them as young as 13 and 14. Twelve officers were also injured in separate rioting Friday in Londonderry.First minister blamedOther political parties blamed the Democratic Unionist Party (DUP) of Northern Ireland First Minister Arlene Foster on Saturday for stoking tensions with staunch opposition to the new trading arrangements.”By their words and actions they have sent a very dangerous message to young people in loyalist areas,” said Gerry Kelly, a lawmaker from the pro-Irish Sinn Fein party, which shares power in the devolved government with the DUP, in a statement.A DUP lawmaker, Christopher Stalford, said rioters were “acting out of frustration” after prosecutors opted not to charge any members of Sinn Fein last week for alleged breaches of COVID-19 restrictions.The DUP has called for the head of the police force to resign over the issue.The British-run region remains deeply split along sectarian lines, 23 years after a peace deal largely ended three decades of bloodshed. Many Catholic nationalists aspire to unification with Ireland while Protestant unionists want to stay in the U.K. 
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