A swastika banner hung from a building on the campus of New York University Wednesday during graduation week. Swastikas flanked both sides of a Star of David in the center of a flag that resembled the purple banners hanging from the university’s buildings.

While graduates attended a graduation party called Grad Alley, a block party featuring live music, carnival games and dances, people in the crowd noticed the flag fluttering from the Steinhardt School overlooking Washington Square. The flag was taken down after about 15 minutes.

Police responded to a call about harassment at 5:21 p.m. and took a report from a man who said that someone had altered the flag to add the swastikas. A police spokesperson said the investigation is ongoing, and no arrests have been made.

“We are shocked and deeply troubled that this hateful symbol expressing antisemitism was raised on a flagpole overlooking Washington Square Park,” N.Y.U. spokesperson Wiley Norvell said in a statement. “Campus safety responded immediately to remove it, and we are working closely with the N.Y.P.D. to identify whoever is responsible.”

Students had previously objected to the choice of Jonathan Haidt as a commencement speaker, complaining that the psychologist opposed diversity, equity and inclusion initiatives. It’s unclear if the incidents are linked.

The president of the school’s Hillel chapter expressed gratitude for the swift removal of the offending flag in a statement.

“There is a clear difference between political expression and invoking Nazi symbolism to portray Israel or Jews as equivalent to the perpetrators of the Holocaust,” she said. “That comparison is deeply offensive, historically distorted and antisemitic, and symbols tied to the genocide of millions of Jews have no place on our campus.”

NYC Mayor Zohran Mamdani, whom critics have blamed for stoking an atmosphere in which antisemitic activity flourishes, denounced the act in a statement on X.

“I am outraged that a swastika flag was raised overlooking Washington Square Park,” he wrote. “This hateful antisemitic act was meant to spread fear among and intimidate Jewish New Yorkers. It has no place in our city.”

“Our administration is committed to fighting antisemitism in all its forms and protecting the safety of Jewish New Yorkers,” he added. “The NYPD Hate Crime Task Force is investigating this despicable act, and I am confident those responsible will be held accountable.”