BELFAST, Northern Ireland (AP) — Crowds from Protestant and Catholic communities hurled bricks, fireworks and gasoline bombs at police and each other in Belfast overnight, as a week of street violence escalated. Police and politicians are trying to calm the volatile situation Thursday in Northern Ireland, where Britain’s exit from the European Union has unsettled an uneasy political balance. The focus of the violence was a concrete “peace wall” in west Belfast that separates a British loyalist Protestant neighborhood from an Irish nationalist Catholic area. As the two sides clashed across the wall, nearby a city bus was set on fire. Police Service of Northern Ireland Assistant Chief Constable Jonathan Roberts said the mayhem “was at a scale we have not seen in recent years.”