Northern Ireland police faced a barrage of petrol bombs and rocks on Thursday, an AFP journalist said, as violence once again flared in Belfast despite pleas for calm. Riot police on the republican side of the divided city were pelted with projectiles as they tried to prevent a crowd moving towards pro-UK unionists. British Prime Minister Boris Johnson and Irish counterpart Micheal Martin had earlier called for “calm” following days of violence that included a petrol-bomb attack on a moving bus. Martin and Johnson held telephone talks in which they stressed that “violence is unacceptable” and “called for calm”, the...