Rioters clashed with police in Ballymena, and masked groups set fire to a recreation center in Larne, where families had been given temporary shelter.

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.

The police said that attacks on houses and businesses in the town of Ballymena were being investigated as racially motivated, and that 15 officers had been injured.