A victims' group spokesman group has made a formal complaint to police after a priest compared unionists to Nazis over their treatment of Catholics.
Fr Alec Reid said Catholics had been "treated like animals"
Willie Frazer of Families Acting for Innocent Relatives, which represents victims of IRA violence, made the complaint against Father Alec Reid.
The priest made the analogy at a public meeting in Belfast on Wednesday. He has since apologised.
Mr Frazer had been involved in a heated exchange with Father Reid at the time.
Father Reid, who witnessed IRA decommissioning, said he had lost his temper.
The PSNI confirmed they had received a complaint following an alleged incident at a public meeting on Wednesday evening.
After the meeting, Father Reid said he had been provoked and offended by comments made by some members of the audience questioning his integrity. He said he regretted the language he had used.
However, unionists strongly condemned his comments.
NI Secretary Peter Hain also told the House of Commons that he joined in the condemnation of Father Reid's remarks.
The public meeting was held at Fitzroy Presbyterian Church in south Belfast. About 200 people were in the audience.