Organizers of South Boston’s legendary St. Patrick’s Day parade say Mayor Martin J. Walsh strong-armed them into inviting an LGBT group to march by threatening to withhold necessary permits, according to court documents filed yesterday.

“The Mayor of Boston has the authority to issue or not issue parade permits in the City of Boston,” attorney Chester Darling wrote in an amended complaint. “Mayor Walsh has repeatedly attempted to alter or control the Plaintiff’s parade, by acts which are violations of the time, place and manner jurisprudence.”

The new filing, which is part of a lawsuit initially filed in March, accuses Walsh and Boston police Commissioner William B. Evans of violating the constitutional rights of the South Boston Allied War Veterans Council. The federal suit asks for “permanent injunctive relief” against the city for what it calls “coercive and threatening acts.”

“The calls were coming from City Hall left and right, and the word was that the veterans were going to lose their parade,” Darling told the Herald yesterday. “He sat there and said he was going to change the content of the parade.”

Walsh vehemently denied the allegations.

“It’s not true, it’s completely not true,” Walsh told the Herald last night. “I don’t know what veterans are claiming that, but they should call me if there’s an issue.”

It’s just the latest accusation against the Walsh administration of using permits to bully organizations. Ken Brissette and Tim Sullivan, both Walsh aides, have been federally indicted on extortion charges. Prosecutors say they threatened to withhold city permits from the Boston Calling Music Festival until it hired union stagehands.

“If you look at any other time … Boston Calling or this, this administration did not hold permits for anyone,” Walsh told the Herald last night. “My administration did not withhold permits. It’s sad when the press keeps reporting that we withheld permits when we didn’t.”

In 1995, Darling won a Supreme Court ruling that let the South Boston Allied War Veterans Council exclude gay groups on First Amendment grounds. Now, more than 20 years later, he’s arguing that Walsh and others undermined that decision with bully tactics and red tape.

Darling argues that the veterans council had numerous meetings with Walsh about the 2015 parade, saying Walsh said that if LGBT groups weren’t included he could cancel the parade for “safety reasons.”

A little more than two weeks before the 2016 parade, Walsh called a meeting with the veterans council, according to the suit. Darling said he showed up, but Walsh told parade organizer Tim Duross that “I will meet with you, but no attorneys,” according to the suit.

“We went into the office — we had Chester Darling with us — and when the mayor saw him there, he refused to let him in,” Duross told the Herald last night. “I refused to go in. I wasn’t going to go in without a lawyer.”