Police say unrest has been organized by 'disaffected groups with links to criminality'

Community leaders have called for calm in Northern Ireland after an increase in post-Brexit tension in recent weeks led to outbreaks of violence over the past few days.

Senior police officers and politicians have added their voices to the pleas for a de-escalation of inflamed rhetoric and lawlessness that have exposed long-established sectarian divides, with disorder in pro-British neighborhoods resulting in 41 police officers being injured in one week.

Arlene Foster, Northern Ireland's first minister and the leader of the Democratic Unionist Party, is one of those who claims to speak for people in the pro-British neighborhoods where the violence has flared.

She told the Financial Times "malign influences" had been stirring up trouble that has included youths setting fire to vehicles and throwing stones and petrol bombs at the police.

"It has to stop, and it has to stop immediately," she said. "Please, desist from this violence. There is a better way, and the way is through politics."

Loyalist leaders have said many people in the pro-British areas are unhappy with parts of the Brexit trade deal that accompanied the United Kingdom's exit from the European Union. The Northern Ireland Protocol, they say, has led to the province being treated differently to the rest of the UK, which they fear opens the door to so-called republicans being able to eventually separate the region from the UK.

The resurgence in sectarian tension involving groups wanting Northern Ireland to remain part of the UK and opponents wanting it to break away is reminiscent of unrest that was effectively ended with the signing of the Good Friday Agreement in 1998.

Chief Superintendent Davy Beck, an area commander of the Police Service of Northern Ireland, said the unrest is being organized by "disaffected groups with links to criminality".

"I appeal to all people with influence to use that influence to put a stop to this," The Financial Times quoted him as saying. "This is a choice, this doesn't have to go on. This can be brought to a conclusion today."

Prime Minister Boris Johnson's office called the flaring of violence "completely unacceptable" and said the government is working with the EU to address issues resulting from the Northern Ireland Protocol portion of the Brexit trade deal.

The Guardian newspaper noted that the EU's ambassador to the UK has, however, insisted that political elements that want the Northern Ireland Protocol to be reworked have offered no alternative suggestions for how a hard border can be avoided on the island of Ireland while different rules and regulations are enforced on either side of that border.

Joao Vale de Almeida said politicians who represent the loyalist community should, instead, focus on making the Northern Ireland Protocol work.

"The protocol is the solution for the problems created by Brexit in Northern Ireland and that's where I believe we should focus," he said.

Northern Ireland's devolved Parliament was set to return early from its Easter break on Thursday, after being recalled to debate the escalation of violence and how it might be ended.