Updated: 5:30 p.m. EST

NEW YORK — New York City Mayor Bill de Blasio will not be marching in the nation’s largest St. Patrick’s Day parade, deciding to skip one of his city’s signature celebrations because the event organizers refuse to let participants carry pro-gay signs.

De Blasio will become the first mayor in decades to sit out the traditional march along Fifth Avenue.

“I will be participating in a number of other events to honor the Irish heritage of this city,” said de Blasio on Tuesday during an unrelated press conference at City Hall. “But I simply disagree with the organizers of that parade.”

The parade, a tradition that predates the city itself, draws more than 1 million people each March 17 to line one of Manhattan’s most famous thoroughfares to watch about 200,000 participants. It has long been a mandatory stop on the city’s political trail, and will include marching bands, traditional Irish dancers and thousands of uniformed city workers.

Since the 1990s, the event’s ban on pro-gay signs and banners has spurred protests and litigation and led to the creation of an alternative, gay-friendly St. Patrick’s Day parade in Queens. In recent years, several elected officials – including de Blasio when he was public advocate – attended the inclusive parade and boycotted the traditional parade.

Though de Blasio’s predecessor, Mayor Michael Bloomberg, was a staunch supporter of same-sex marriage rights, he still marched in the Fifth Avenue parade all 12 years he was in office. Rudolph Giuliani also participated every year he was mayor.

The parade dates from 1762, more than a century before the five boroughs linked to form modern New York City. It is run by a private organization, and judges have said the organizers have a First Amendment right to choose participants in their event.

Groups, such as colleges or firefighter groups that march, can identify themselves but LGBT groups cannot.

A request for comment from the New York City St. Patrick’s Day Parade committee was not immediately returned. Organizers have previously said that the event is simply a celebration of the city’s strong Irish heritage and that gays are welcome to march in the parade as long as they do not carry identifying signs or banners.

The mayor, a Democrat, also said Tuesday that he won’t heed activists’ call to ban city workers from marching while wearing their uniforms.

Several elected officials, including Public Advocate Letitia James, signed a petition r eleased Tuesday that suggested that because members of the lesbian, gay, bisexual and transsexual community could not sport anything to identify themselves, the city workers should also not wear anything to proclaim who they are.

“I believe uniformed city workers have a right to participate if they choose to, and I respect that right,” de Blasio said.

Thousands of uniformed workers – from the police, fire, corrections and sanitation departments – march in the parade every year. The parade’s grand marshal this year is Jack Ahearn, the head of a local operating engineers union.

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