BELFAST — Gangs of youths threw stones and fireworks at police in Belfast who hit back with water cannons as violence flared again on the streets of Northern Ireland.

Unrest has erupted over the past week amid tensions over post-Brexit trade rules and worsening relations between the parties in the Protestant-Catholic power-sharing Belfast government.

The latest violence Thursday night came despite appeals by UK Prime Minister Boris Johnson, Irish Premier Micheal Martin and U.S. President Joe Biden for a calming of tensions.

Police holding riot shields were pelted with missiles before officers charged at the rioters with dogs. Police also used water cannons to disperse the crowds.

Earlier in the day, the Northern Ireland Assembly unanimously passed a motion calling for an end to the disorder, and the region’s power-sharing government condemned the violence

“While our political positions are very different on many issues, we are all united in our support for law and order and we collectively state our support for policing and for the police officers who have been putting themselves in harm’s way to protect others,” leaders of the five-party government said in a joint statement.

“We, and our departments, will continue to work together to maximize the support we can give to communities and the (Police Service of Northern Ireland) to prevent further violence and unrest.”

Northern Ireland has seen sporadic outbreaks of street violence since the 1998 Good Friday peace accord ended “the Troubles” — decades of Catholic-Protestant bloodshed over the status of the region in which more than 3,000 people died.

Britain’s split from the EU has highlighted the contested status of Northern Ireland, where some people identify as British and want to stay part of the UK while others see themselves as Irish and seek unity with the neighboring Republic of Ireland, an EU member.