Photos have surfaced showing a group of men dressed in Ku Klux Klan outfits outside an Islamic prayer house in Northern Ireland.
In a video taken in Newtownards, County Down, on Saturday night, a group of were also seen wearing white robes and pointed hats in a local JD Wetherspoon pub.
Local officials have condemned what happened, after the incident was reported to police at about 5pm on Sunday.
PSNI Insp Richard Murray said: "Hate crime, in all its forms, is totally unacceptable."
The Chief Constable, George Hamilton, told BBC NI's The Nolan Show he felt the incident was 'disgusting and distasteful', adding: "There's no place for it anywhere in Northern Ireland. We will investigate it and report the evidence to the PPS."
Meanwhile, Alliance MLA Kellie Armstrong also referred to the incident as a 'hate crime', saying that the photo of people dressed as members of the white supremacist group was a 'clear demonstration of aggression'.
A photo of KKK members in 1964. Credit: PA
JD Wetherspoon spokesperson Eddie Gershon said that the group had stormed into the pub, despite security trying to keep them out.
He said: "They were refused entry by door staff, but pushed past them into the pub.
"They were told by bar staff that they would not be served. They remained in the pub for five minutes, unserved, and then left."
In the clip, the men are dressed in white robes and pointed white hats that resemble Capirotes - often used as part of the uniform for the KKK. Some people are also holding accessories, including crosses and torches.
Social media users have been slamming the group's actions online, with one writing: "Disgusting and criminal. Hope the police can catch these horrible human beings."
Another wrote: "I never thought this would happen in my country. At least the police are taking it seriously... a little group of little people with little views."
Someone else, using the hashtag #NotInMyName, wrote: "Absolutely disgusted to be living in the same town as these scumbags."
A fourth referred to it as 'abhorrent', but added that is was 'sadly not surprising'.
Belfast Islamic Centre executive treasurer Dr Raied Al-Wazzan said the Muslim community in Newtownards had been left shaken by the incident.
"They could have gone to anywhere in Newtownards, anywhere in Northern Ireland dressing in any uniform, but to go in front of an Islamic prayer room, it's totally making people afraid," he told The Nolan Show.
"They are afraid to come out or even to go there."
Acknowledging that it could well have been a Halloween stunt, Al-Wazzan urged those involved to come forward and identify themselves.
"If they keep it quiet for the next 24 hours, that means it was a deliberate act," he said.
"If this is just a joke, these people should come forward and identify themselves.
"To go there specifically wearing that costume in front of the Islamic centre is not acceptable. It's similar to somebody wearing a Nazi uniform and going in front of a Jewish synagogue."
Featured Image Credit: BBC