BELFAST — Violent clashes in Northern Ireland erupted over the weekend amid increasing tensions in a region historically plagued with sectarian violence. Sunday marked a third night of disorder in the cities of Belfast and Derry/Londonderry, where police were targeted with petrol bombs and cars hijacked and set alight. The clashes involved children as young as 12, according to a statement from the Police Service of Northern Ireland (PSNI). On Saturday night 30 petrol bombs were thrown at police in Newtownabbey, Belfast, and three vehicles were hijacked and set on fire, police said, in what they described as an "orchestrated attack." It followed riots on Friday across both cities following a decision not to prosecute leaders of the Irish nationalist party, Sinn Fein, for allegedly breaking coronavirus restrictions by attending the funeral of a former leading IRA figure during lockdown last year. The decision is being reviewed. It also comes amid rising anger over a specific part of the Brexit withdrawal agreement, called the Northern Ireland Protocol, which aims to eliminate the need for border controls between Northern Ireland — which is part of the UK — and the Republic of Ireland, an EU member. Instead, it creates a de facto border down the Irish Sea as goods entering Northern Ireland from Great Britain are subject to EU checks -- a move which has angered pro-British Unionists. Police deemed the escalating violence as "unacceptable" and appealed to residents to help diffuse any local tensions and prevent further incidents. David Campbell, chairman of the Loyalist Communities Council, recently told CNN that "it"s very easy for matters to spiral out of control, that"s why it is essential for dialogue to take place... but [if not] for the Covid restrictions there would already have been demonstrations — I"ve no doubt the ports would have been blockaded." Democratic Unionist Party MP Sammy Wilson told CNN"s Nic Robertson on a recent trip to Northern Ireland: "We"re simply saying to tear up the agreement which breaks up the United Kingdom, tear up the agreement which breaks up all the promises you made to the people of Northern Ireland that you would have unfettered access to your biggest market in GB (Great Britain)." Speaking about Friday"s incident, Sinn Féin MP Paul Maskey said in a statement: "This evening we have unfortunately seen running skirmishes between young people and the PSNI in the Sandy Row area following a protest that was organized by loyalists against the protocol." "I appeal to the DUP and political unionism to show leadership, to end their dangerous rhetoric and to ensure there is an urgent de-escalation of tensions," Maskey added. — Courtesy CNN