Elected officials denounced white supremacy after dozens of fliers bearing the words “Keep America American’’ were found plastered around East Boston’s Eagle Hill neighborhood Thursday night.

“Boston is strong because of its diversity and the neighborhood of East Boston has been a beacon for immigrants for centuries. Our communities are interconnected, interdependent and our growth as a city relies on a future of mutual, and cross-cultural, admiration, tolerance and respect,’’ Mayor Martin J. Walsh, state Senator Joe Boncore, state Representative Adrian Madaro, and Boston City Councilor Lydia Edwards said in a joint statement released Friday morning.

“Boston rejects hatred, racism and promotion of white supremacy in all forms. These ideas are toxic to our society and contribute to physical violence, economic disparity and division along lines of race, class, nationality and origin,’’ the statement said. “While we must always uphold a free exchange of ideas, hatred that demeans individuals or groups based on who they are, how they look or where they come from is not welcome in Boston. Those seeking to promote bigotry will always fail in the face of unity that is stronger, lasting and more resilient.’’

Walsh has spoken with Police Commissioner William Gross about the incident and has asked for an investigation, according to the mayor’s office.

An official police report had not been filed as of Friday afternoon, said Officer James Moccia, a spokesman for the Boston Police Department.

Madro said he would like to see an investigation into who put up the fliers.

“We don’t know if it was done by people in the community or if it was targeted,’’ Madaro said in a telephone interview Friday.

Madaro described Eagle Hill as one of the most diverse areas in a diverse neighborhood and said he is discussing with other elected officials who represent East Boston ways to support the community after the incident.

Multiple versions of the poster were attached to utility poles and trees, some listing a web address for a white supremacist group, the Patriot Front.

When Phil Haggerty returned to his East Boston home after work Thursday night, he saw posts about the posters in a Facebook group for neighborhood residents.

He and his girlfriend, Olivia Mignosa, who also lives in East Boston, decided to take a walk with their dogs and rip down the posters. Haggerty said he collected more than 50.

Many of the fliers included the name of the Patriot Front.

“Patriot Front is a white supremacist group whose members maintain that their ancestors conquered America and bequeathed it solely to them,’’ according to the Anti-Defamation League.

One of the posters depicted a muscular man carrying an American flag. Above the image of the man in bold font were the words: “Patriots! Reclaim your birthright.’’

Another poster read, “Keep America American . . . Report any and all illegal aliens. They are not immigrants, they are criminals.’’

Haggerty said he believed East Boston was targeted for its diversity. “It’s certainly not an accident that they targeted East Boston specifically,’’ Haggerty said in a telephone interview. “At its core it’s an immigrant community, and this was an intimidation tactic.’’

Haggerty said he thought that they might have been put in place sometime after 10 p.m. Thursday.

“They’re cowards,’’ he said. “They did it intentionally while no one was out,’’ he said.

Ripping down the posters was the least he could do, Haggerty said.

“These people [who made the posters] are not welcome in this neighborhood,’’ he said.

Maddie Kilgannon can be reached at maddie.kilgannon@globe.com.