Rioters attacked police with petrol bombs, rocks and fireworks in the Northern Irish town of Portadown on Thursday, a Reuters witness said, as a fourth night of anti-immigrant violence moved to a different part of the British-run province.

Protests in the small Northern Irish town of Ballymena spiralled into acts of anti-immigrant violence this week after two teenagers who spoke Romanian were charged with sexually assaulting a local girl.

Homes, businesses and cars have been attacked and 32 police officers injured during violence in Ballymena and several other areas in Northern Ireland.