Belfast: Rioting 'was worst seen in Northern Ireland in years'

NI's power-sharing executive has said it is "gravely concerned" by recent street violence and has called for calm to be restored.

During several hours of rioting in Belfast on Wednesday, police were attacked, petrol bombs were thrown and a bus was burnt.

The Police Federation said seven officers were injured at an interface between loyalist and nationalist areas.

The prime minister also condemned the violence.