A total of 27 police officers have been injured in unrest in Northern Ireland as political leaders call for calm over the Easter weekend.The PSNI said 15 officers were injured in Belfast and 12 officers were hurt in Londonderry during riots in both cities on Friday evening.Eight people have been arrested.Derry City and Strabane Area Commander Chief Superintendent Darrin Jones said police received reports on Friday night of youths gathering in the areas of Nelson Drive and Tullyally in the city.
