A group of Israeli teen ultimate Frisbee players were banned from an international competition in Belgium last week after a vandal scrawled antisemitic statements near their playing field — and the heartbroken kids and coaches are wondering why.

The Israeli delegation — which included 33 players between the ages of 13 to 16, as well as nine adults — had been practicing and preparing for years ahead of the European Youth Ultimate Championship in Ghent, Belgium, according to Chen Bankirer, president of the Israeli Flying Disc Association.

But just as the team — which traveled thousands of miles to get to the tournament — was getting ready for Tuesday morning’s inaugural games, the tournament director told them that somebody had spray-painted “Boycott Israhell now!” near their field.

That’s when the city’s mayor and police stepped in — and told the team it couldn’t participate.

Daniel Ben David, a 22-year-old assistant coach who lives near Tel Aviv, said that the Ghent police chief told the adults that “This is your war, not mine,” before saying their presence would cause problems in Belgium.

“It’s just very antisemitic, honestly,” the coach added. “We just want to let our kids play. We aimed to win this tournament, we’ve been working for three years just to prepare. And to have it robbed from the kids is horrible.”

Bankirer told The Post that the local officials tried to claim they were concerned for the team’s safety.

“Basically they said to us, ‘You’re not going to play. The claim of the police and the city is that the fields are too open, and they cannot protect the fields [or] ensure the safety of the tournament,” he said.

“We heard the news on Tuesday morning at 6 a.m.,” he said. “We were sad. We were waiting for [the kids] to wake up. And then we gathered all of them together, and we broke the news to 33 kids that they cannot play because they’re Israelis. And they were heartbroken.”

The Israeli Foreign Affairs and Culture and Sports Ministries tried to intervene, but the final decision banning the teams was made Tuesday night, according to The Jerusalem Post.

To add insult to injury, the city also banned the kids and coaches from even watching the games as spectators.

“I think they did not want people around to know that there were Israeli Jewish people there,” Bankirer said.

Ben David said that telling the kids they couldn’t play was gut-wrenching.

“Seeing their faces when we told them the news … it was one of the hardest things I’ve ever had to see,” he said.

“They were devastated,” he continued. “I had to keep a facade of being strong and fine, but deep inside, I was so hurt and disappointed just to see them like that — they deserve to play.”

Itamar Kaplun, the team’s 16-year-old captain, said that calling the city’s decision shocking would be an understatement.

“It was like everything I worked for, someone just snapped, and it was gone,” Kaplun said. “I couldn’t eat. I couldn’t talk.”

There hadn’t been any problems at the tournament until then, he said. And the Israeli team had gotten along with everyone else there.

“I was surprised that for 15-year-old kids who worked for three years … They just took it away from us,” he said. “And to find out in such a difficult way — because there was no way to say it easily — it was heartbreaking.”

“It’s kind of a reality that, as a Jew, you have to get used to it at some point.”

Bankirer said he and the coaches appealed to both the tournament organizers and local officials, but didn’t get anywhere.

The European Ultimate Federation blamed the city for the decision and said it was out of their hands, he added. And the city wouldn’t budge off its decree.

Bankirer instead brought the kids to local Jewish fields, where they spent their time playing ultimate Frisbee on their own.

“Basically, we were winging it,” he said. “So we played.”

But the story likely isn’t over.

Bankirer said they filed formal appeals with the organizations that run the tournament. And they plan to sue over the affront.

But the damage has been done.

“This is something that should be in the heart — and the basis — of every single sport,” he said. “An international event has to be able to include everyone. Or not exist.”