Germany's leading airline has been fined $4 million by the U.S. Department of Transportation over allegations it discriminated against a group of Jewish passengers, according to NBC News.

The regulator said Tuesday that Lufthansa barred 128 people dressed in traditional Orthodox Jewish clothing from boarding a connecting flight in Germany as they traveled from New York to Budapest, Hungary, in May 2022.

“Based on the alleged inappropriate behavior of some passengers, Lufthansa staff treated all of them as if they were one group and denied them boarding, despite the fact that many of the passengers did not know each other and were not traveling together,” the regulator said.

Some group members allegedly violated the airline's policy on mask use. Video footage of the incident at the time shows Lufthansa staff telling passengers that “everyone has to pay” for the mistakes of some, and then identifying “everyone” as “a Jew who came from JFK airport”.

It is the largest fine ever imposed by a U.S. regulator on an airline for civil rights violations.