BOSTON — The Dropkick Murphys are hitting back against a neo-Nazi group that used one of the rock band’s songs in a video posted on social media.

The rowdy rockers from Boston condemned the use of the song “The Boys are Back” in a tweet, while the band’s attorneys sent a cease-and-desist letter to the group as well as to the platform that shared the video.

After calling them “losers,” the band wrote “Stop using our song for your little dress up party video. We will SMASH you,” in response to a tweet from a man who confronted the group at South Boston’s St. Patrick’s Day parade last weekend.

About a dozen masked members of the group, known as NSC 131 or the Nationalist Social Club, attended Sunday’s parade as spectators and held up a banner that said “Keep Boston Irish.” Their appearance was denounced by the parade’s organizers and Mayor Michelle Wu.

The video posted on the video-sharing platform Odysee documents the group’s appearance at the parade as the song containing the refrain “The boys are back, and they’re looking for trouble” plays.

“DKM has not (and would not, ever, in a million years) authorize or license to NSC 131 the right to use or exploit the Recording and/or Composition in the video in question or any similar video,” said the cease-and-desist letter dated Tuesday from the band’s Los Angeles-based attorneys. The band’s publicist confirmed the letter’s authenticity to Boston.com.

It went on to say: “We’ll take your immediate compliance as confirmation that you received this letter. If, however, you fail to immediately comply, then my client and their designees and assignees are prepared to take whatever legal action they deem necessary and appropriate to protect their rights in and to the Recording and Compensation, including, without limitation, seeking statutory and punitive damages for your copyright infringement.”

Odysee in an email to The Associated Press on Friday said it complies with copyright law, and the video was reviewed and subsequently taken down.

The Anti-Defamation League says NSC 131 is a New England-based neo-Nazi group founded in 2019 that “espouses racism, antisemitism and intolerance” and whose “membership is a collection of neo-Nazis and racist skinheads, many of whom have previous membership in other white supremacist groups.”