The PSNI has rejected claims by Sinn Féin that officers were heavy-handed during rioting in Derry city centre during the early hours of yesterday morning.
Police said several hundred people were involved in the disturbances and that the response was proportionate.
Five PSNI officers and one civilian were injured during the trouble.
However, Sinn Féin said eyewitness reports pointed to events spiralling out of control after a large number of police officers intervened in a relatively minor scuffle between two individuals.
Foyle MLA Martina Anderson has called for Northern Ireland's Police Ombudsman's Office to investigate what happened.
