Speaking after an Easter Monday parade in Derry/Londonderry, Area Commander of Derry City & Strabane Chief Superintendent Gillian Kearney said: "Despite the claim by organisers of today's Easter Monday parade who said they wanted to hold a dignified commemoration, what we saw was the complete opposite.
"From the commencement of the parade to when it dispersed, we saw masked individuals, which we believe at this time to be a breach of the Parades Commission determination.
"As these masked individuals made their way towards the dispersal point on Lecky Road, disorder developed in the area of Nailors Row from around 2.50pm. Petrol bombs, fireworks and masonry were thrown which resulted in nearby Bishop Street (Without) being closed for a time for public safety reasons. Members of the public were diverted away from that area in the City Walls.
"This disorder involving young people was orchestrated. We have no doubt about this.
"Young people were shamelessly and deliberately used in an attempt to distract from and shield the masked individuals as they took cover in a gazebo following the parade in the area of St. Joseph's Place to change out of their parade clothing.
"This is child criminal exploitation. It is utterly shameful."
Following the parade, as part of a proactive policing operation, officers stopped two vehicles - one in the Frances Street area and one in the Fanad Drive area. Two men, aged 30 and 55, were arrested under The Terrorism Act and have been taken to Musgrave Street Station for questioning.
One of the vehicles stopped (a van) was seized. A number of items were also seized.