PORTADOWN, Northern Ireland (Reuters) -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.

Two 14-year-old boys were accused of sexually assaulting a teenage girl. The charges were read to the teenagers via a Romanian interpreter, the BBC reported. Police are investigating attacks on four houses as racially-motivated hate crimes.