Two people were reportedly bitten by a police dog at Belfast's Central Station yesterday after a crowd of train passengers became involved in disturbances inside the station.
There were no arrests but PSNI officers received a report that a man and woman were both bitten by a dog during the disorder.
A PSNI spokesman said the matter will be referred to the Police Ombudsman's Office.
Translink, the company which runs the station, said railway staff called police for help yesterday afternoon because of "anti-social behaviour by some of our passengers".
A spokeswoman said the incident took place over a period of two hours from 4.45pm to 6.45pm and involved "quite a number of people".
Translink cancelled one train service on the Belfast to Larne line shortly before 6pm "due to disruptive passengers".
Elsewhere, in a separate incident, six men were arrested in Ormeau Park for a number of public order-related offences.
There was also disorder in Castlereagh Street, east Belfast, during which a man in his 40s was arrested.
Meanwhile, a man in his 20s was taken to hospital after a stabbing in west Belfast.
The attack happened in the Lenadoon Avenue area at around 8.20am yesterday morning.
Police said his injuries were not life-threatening.
Anyone with information in relation to the attack should contact police on the new non-emergency number 101.