Delta has been fined $50,000 after the federal Transportation Department found that it discriminated against three Muslim passengers who had been cleared by the airline’s security but were barred from flights, according to a consent order.

The airline was also mandated to make some flight crews and customer service representatives attend civil rights training as part of the department’s order, which was issued on Friday. The passengers had filed complaints against Delta with the agency.

The order addressed two episodes that took place in July 2016, and involved flights from Paris to Cincinnati and from Amsterdam to New York. In both instances, the captain of the flight overruled Delta security officials, who had said the passengers passed background checks, agency officials said.

In both cases, Transportation Department officials said, Delta crews failed to follow the security protocol and their decisions to bar the passengers from the flights were discriminatory.