(JTA) — Dutch Chief Rabbi Binyomin Jacobs called on authorities to identify and punish high school pupils who during their graduation ceremony sang about burning Jews. The incident happened last week during the graduation gala of the Elde College in the town of Schijndel, 70 miles southeast of Amsterdam.

Several graduates sang: “Together we’ll burn Jews, because Jews burn the best.” The phrase is part of a chant heard several times in recent years during soccer matches connected to the Amsterdam’s Ajax football team, whose players and supporters are often dubbed “Jews” because of the historic Jewish presence in the city. The student body and organizing committee of the Elde College gala expressed their sincere apologies for the incident, but Jacobs said the guilty parties “must be prosecuted for hate speech.”

The frequency of antisemitic chants and other hate crimes “means Dutch Jews are less inclined to report hate crimes, when they occur around them all the time,” Jacobs told JTA. His home in Amersfoort has been attacked five times in recent years. Jacobs referenced the incident during his speech earlier this week in Vught, at a ceremony for Jewish Holocaust victims at a former Nazi internment camp. “Only six years ago, we were profoundly shocked when two young men screamed ‘Heil Hitler’ during a commemoration ceremony at Vught,” he said. “But today, this wouldn’t be so shocking anymore. It is happening all the time in the Netherlands, and we must face this change with honesty, and combat it with education and severe punishments for violators.”