The Board of Deputies have said it is “beyond disgraceful” that a Labour councillor appeared to have written "Hitler had the right idea, anyone got any gas canisters?" in a discussion about Travellers.
Bob Murray, a councillor in Prestatyn, Wales, answered "no comment" when the Local Democracy Reporting Service contacted him ask whether he was responsible for the post and whether he would be resigning.
Prestatyn county councillor Paul Penlington, who is also a Labour member, said he had complained about the "vile" post to council bosses after that he was alerted to the post in a discussion thread about a small group of local travellers.
Cllr Penlington said: "On Wednesday April 3, I put a post on Facebook, informing residents of Denbighshire Council's sensible response to a small group of Travellers in my ward.
"I only stated the facts to avoid any misinterpretation as this can be a contentious subject for many people.
"On Thursday, later in the evening, a post appeared on the thread making a vile racist statement.
"The post was in the name of another councillor. Fortunately I saw it within five minutes of it being posted and I deleted it very quickly. I passed it on to the Labour group leader and Denbighshire council head of legal services immediately.”
In a statement on Monday, the Board said: “It is beyond disgraceful that anyone would make this kind of genocide-supporting comment, much less an elected councillor.”
They added that Cllr Murray was “not fit for office” and called on Labour to expel him.
Holocaust Educational Trust Chief Executive Karen Pollock said: “These are vile and offensive remarks, directed at a minority group. They are not befitting of anyone, especially someone in public office.”
Trudy Aspinwall, of Travelling Ahead, a Traveller, Roma and Gypsy rights group, said: "These appalling comments published on an on-line public platform are a hate crime. We have reported it as such this morning and will also be calling on the Labour Party in Wales to take action.
"This casual acceptance of racism against Gypsy, Roma and Traveller communities cannot be tolerated any longer. It would be absolutely unacceptable to say this publicly about any other group, and it's particularly concerning if this comes from a publicly-elected representative who has a role in decision making about local plans to improve services for this community."
A Denbighshire Council spokesperson said: "The matter was referred to the council and we have since referred it to the Public Services Ombudsman for Wales for consideration. We cannot comment further at this stage."
Labour said complaints about discriminatory and threatening language were taken "extremely seriously".
