It was a beautiful day for soccer in the Dutch town of Utrecht. Spring sunshine filled the stadium as the local team, FC Utrecht, kicked off against perennial powerhouse Ajax Amsterdam.

As the beautiful game slowly played out on the field, however, things in the stands quickly got ugly.

“Hamas, Hamas, Jews to the gas,” sang a section of the home supporters towards the fans visiting from Amsterdam, a city historic in part for its Jewish community. “My father was in the commandos, my mother was in the SS, together they burned Jews, because Jews burn the best!”

The anti-Semitism was caught on video and quickly circulated among Dutch media. FC Utrecht issued an apology as Jewish organizations demanded action by soccer authorities.

The shocking chants weren’t an isolated incident, however. Instead, they were the latest in a string of anti-Semitic episodes that threaten to mar European soccer.

Discrimination isn’t new to European football, or soccer. The sport has long struggled with racism, a problem which resurfaced recently when Chelsea fans pushed a black man off the Paris metro, chanting: “We’re racist, we’re racist, and that’s the way we like it.”

“We’ve had issues like this since the ’80s,” said Shimon Samuels, director for international relations at the Simon Wiesenthal Center, a human-rights organization.

But anti-Semitism in European soccer appears to be getting worse. According to Kick It Out, a British organization originally devoted to combating racism, anti-Semitic incidents are up in the English Premier League. A Kick It Out study released last month revealed that there were 59 reported instances of anti-Semitism during the first half of this season. That was more than during the entire previous season. Anti-Semitism made up a third of the total instances of abuse, and was second in frequency only to racism.

One of this season’s worst episodes came when fans of the London club West Ham were caught on camera chanting “I’ve got a foreskin, how about you? F—— Jew” on their way to play Tottenham Hotspur, a team with a historically strong Jewish following. (Last year, several Tottenham supporters were arrested for chants referring to themselves as “Yids,” a derogatory name that some Hotspur fans have reclaimed.)

Other recent incidents have included fans — and in several instances players — making Nazi-like salutes.

For the past decade, European soccer organizations have fought a public battle against racism. But now anti-Semitism appears to have emerged as a second front.

Samuels said anti-Semitism in soccer is different today than it was decades ago.

“I think there is a shift going on,” he said. “The troublemakers way back to the 1980s … were neo-Nazis. Today it’s a combination. It’s a new alliance between neo-Nazis and jihadists. In the first instance it’s the old anti-Semitism but also there is an understanding that as you attack the Jew as the quintessential symbol of Europe, you also attack the West and you attack the delicate fabric of liberal democracy.”

To support his claim, Samuels pointed to a recent game between Bosnia and Austria. Bosnian fans took to the streets of Vienna in what was originally a pro-Palestine demonstration, but eventually disintegrated into chants of “Kill, kill the Jews” — also caught on video.

Samuels said anti-Semitism in soccer is part and parcel of a bigger problem in Europe. “It’s a sort of chicken and egg relationship,” he said. “Football is vulnerable, because it’s very difficult to control fans.”

But Ronny Naftaniel, Chairman of the Dutch Jewish Humanitarian Fund, sought to draw a line between the chants — as insulting as they are — and anti-Semitism. Whether it’s West Ham vs. Tottenham or Utrecht vs. Ajax Amsterdam, he said such insults have more to do with local rivalries than true bigotry. (The Bosnia case was an exception, he said.)

“It’s indeed very shocking what happened at the game between FC Utrecht and Ajax,” he said. “It’s something that happens twice or three times a year during games. And it looks as if no one is able to fight it. Of course, it has some deeper roots which go back to the fact that Ajax supporters, they expose themselves as Jews. They walk with flags with the Star of David and they call themselves ‘The Jews.’ So the problem is that then their adversaries act as if Ajax are the Jews and come up with the most insulting slogans.”

“For us Jews, we are disgusted,” he said. “But those people who do those slogans are not Nazis. They are not most of them fundamentalists whatsoever. They are supporters, hard core supporters, of those clubs. But we don’t want to hear it. For us, these are insults. For us, it is horrible after what happened in the second World War and in the gas chambers.”

Even if those behind the FC Utrecht fans aren’t really neo-Nazis, that doesn’t mean the problem isn’t a vexing one.

“If these were hard core anti-Semites, it would be easier to combat it,” he said. “But it’s part of the football culture, and that is very tough to fight against.”

Progress is slow and difficult, but not impossible, he said. Such anti-Semitic chants were once entrenched in The Hague, the symbolic heart of European justice. Supporters of the local team, ADO Den Haag, used to chant “Hamas, Hamas, Jews to the gas” whenever Ajax came to town, Naftaniel said. They even made a sickening sound, as if gas were slowly leaking into the stadium.

But ADO cracked down on the chants, enforcing lifetime bans for offenders and installing audio and video technology to catch perpetrators, Naftaniel said. “The leadership of the club really started to fight it,” he said. “That indeed helped.”

Both Naftaniel and Samuels said there is an even easier and perhaps more effective way of combating anti-Semitic chants.

“Walk off the field,” Naftaniel said, referring to the Ajax players and coaching staff. “Then a kind of national debate would start. If Ajax said, ‘we won’t play if they tell us to go to the gas chamber,’ then that would have helped.”

Stopping games forces everyone in attendance to take the chants seriously, Samuels said.

“When the referee calls a halt and they walk of the field, this makes the perpetrator, the spoiler, into a villain for those people who honestly came for their love of the beautiful game of football and paid good money for it and came from distances,” he said. “So they say, ‘Why they hell should we have to be bothered by these nuts or hate mongers?’

“You have to turn the thing around and have the public understand that this is in their best interests,” Samuels said. “If they really want to watch football, then football cannot be politicized.”