The Boston “antifa” group lumped the thin blue line pro-police symbol with a list of white nationalist, neo-nazi and alt-right logos, enraged NYPD union officials said Monday.

The thin blue line symbol is used to show support for law enforcement and commemorate fallen members who died in the line of duty and has become a symbol of police pride across the country and abroad. However, during the antifa protests in Boston over the weekend, it was shown on one of their posters as a symbol of hate to watch out for, next to images of an alt-right flag and a neo-nazi flag.

“Learn to identify these symbols and let anyone displaying them know that they are not welcome in our city! Boston is an anti-fascist zone!” the poster reads.

The Sergeant’s Benevolent Association in New York sent an email out to its members denouncing the association.

“What is happening in this country is a disgrace and the fact that a police symbol is lumped into the White Nationalist/ Neo-Nazi/ Alt-Right grouping just shows you how ignorant and reactive people can be,” the email reads.

“This behavior is horrible and we, along with our brothers and sisters across this nation, detest it!”

The SBA said officers and their families who display thin blue line symbols could be “misinterpreted as supporters of White Nationalist groups.”

“You must be aware of this fact and educate your family and friends. Be aware of your surroundings at all times, stay vigilant, watch each other’s backs,” the email warns.