Stickers which appear to promote white supremacist views have been posted outside a primary school.
The stickers, found at Scarcroft Primary School in York on Tuesday, were branded "disgusting" by parents.
Police said they were aware of similar posters appearing elsewhere in the city and were actively seeking those responsible.
A local councillor, parent and school governor said "racism and intolerance" were not welcome.
Jonny Crawshaw told the Local Democracy Reporting Service he was loathe to give any oxygen to the group's views but a line had been crossed.
He said: "I don't know who the person behind this is but they do not represent my community or my city.
"The York I know is open and welcoming of all people from any and all nationalities and backgrounds. Racism and intolerance are not welcome here or anywhere."
Another parent at the school, who did not wish to given their name, said: "A place of learning should not be a place of hate.
"Children are typically those most accepting of others and we should learn from them. To push racist views on young children is pretty disgusting."
A spokesperson for North Yorkshire Police said officers had visited the school, adding: "We have been aware of similar stickers appearing around York in recent months and our Prevent officers are working with local policing and the local authority to identify, deter and where appropriate, prosecute, those who spread extremist messages in our community."