Mamdani, the city’s first Muslim mayor, has long been a critic of Israel.

He has accused Israel of committing genocide in Gaza and threatened to arrest Benjamin Netanyahu, the Israeli prime minister, if he visited New York City.

His absence reflects intensifying political shifts and waning American support for Israel, while highlighting deep fractures within the Democratic Party regarding the Israeli war in Gaza.

While Mamdani stayed away,  other elected officials marched in Manhattan on Sunday, including Governor Kathy Hochul and Jessica Tisch, the New York City police commissioner.

Ms. Hochul said at a news conference as the parade started that the group was marching “in defiance.”

Though it has gone by different names over the years, the so-called “Israel Day” parade has always been a must-attend event for mayors, governors and other political leaders eager to win over the large Jewish population in this city.

Not so for Mamdani. Two weeks ago, the mayor’s office released a video commemorating the Nakba, an Arabic word for “catastrophe” that is used to describe the displacement of hundreds of thousands of Palestinians during the 1948 Arab-Israeli war that followed Israel’s establishment.

“I said on the campaign trail that I wouldn’t be attending the parade, and I’ve made my views on the Israeli government abundantly clear,” Mamdani said at a news conference Thursday.

But he also promised a robust police presence to make sure it went off “seamlessly and peacefully.”

“While I will not be attending, our administration has been preparing for weeks to ensure the parade is safe for all those who take part,” he said, AP reported.

Support for Israel among Americans has deeply eroded in recent years, a trend that accelerated amid the outcry over the Israeli genocidal war in Gaza.