Crowds of youths in a pro-British area of Belfast set a hijacked bus on fire and attacked police with stones in the latest of a series of nightly outbreaks of violence that began last week, APA reports quoting Reuters.
British Prime Minister Boris Johnson said he was "deeply concerned" by the violence, which has injured dozens of police officers in recent days as protesters burned cars and hurled petrol bombs at police.
The violence comes amid growing frustration among many in the pro-British unionist community at new trade barriers between Northern Ireland and the rest of the United Kingdom that resulted from Britain's exit from the European Union.
The pro-British Democratic Unionist Party (DUP) have also pointed to a decision by police not to prosecute Irish nationalists Sinn Fein for a large funeral last year that broke COVID-19 regulations.
Sinn Fein in turn have blamed the DUP for stoking tensions with their staunch opposition to the new trading arrangements and their call in recent days for the region's police chief to step down.
The Police Service of Northern Ireland has said some of the violence was influenced by "criminal elements" who helped to orchestrate the attacks.