Labour is calling for an urgent investigation into a Tory MP after she was pictured with two far right activists.
The images of Dehenna Davison were posted on Facebook after a Brexit-themed party on 31 January.
Anti-racist campaigners claim the two men have a history of Holocaust denying and Islamophobic social media posts.
The MP told the Huff Post the party was a public event and she "in no way whatsoever" condoned their views.
The BBC contacted her office, but was told Ms Davison would not be making any further comment.
Labour's shadow equalities minister, Dawn Butler, said the incident was "another example of the serious level of complacency towards the far right by the Tory Party".
She added: "The police have warned that the far right are the fastest growing terrorist threat in the UK, yet we see the Tories proudly fraternising with open racists and neo-Nazis. This must be urgently investigated."
The party took place at The Merry Monk pub in Ms Davison's constituency of Bishop Auckland on the day the UK left the EU.
Campaign group Hope Not Hate claimed one of the men she was pictured with had previously been an active member of the local Conservative Party.
They also said he had organised protests outside the office of the area's former Labour MP, Helen Goodman, with members of the English Defence League and other far right groups.
Local Labour activists said they had flagged his affiliations to Ms Davison in a tweet in 2018 - more than a year before the party took place.
Hope Not Hate said the other man Ms Davison was pictured with, who attended the protests, had posted a stream of social media content celebrating Hitler, along with a photo of him burning the Koran.
They said Ms Davison had "serious questions to answer about her connections".
A statement from Hope Not Hate added: "These allegations are extremely serious and warrant the Conservative Party launching an urgent investigation, during which time Dehenna Davison should be suspended until a finding has been made.
"Davison must explain why she was associating with these two individuals. It is important for our politics generally, and the Conservatives specifically, that the party aggressively rejects any association with the far-right."
Ms Davison won the seat of Bishop Auckland in December, which had been held by Labour since the constituency's creation in 1935.
In a statement, Ms Davison said: "These photos were taken at an event open to the public and I in no way whatsoever condone the views highlighted of the individuals concerned."
The BBC contacted the Conservative Party but they have yet to respond.