By David Shepardson

WASHINGTON (Reuters) -The U.S. Transportation Department said Wednesday it had fined Mexican carrier Volaris Airlines up to $300,000 for violating federal law on airport tarmac delays.

Federal law and government regulations prohibit tarmac delays of four hours or more on international flights without providing passengers an opportunity to deplane.

The department said in 2021 and 2022, Volaris allowed two flights to remain on the tarmac for lengthy periods without providing passengers an opportunity to deplane in Houston and St. Louis. Volaris will pay $150,000 of the fine and must pay the other $150,000 fine if it violates the tarmac rules within a year. The U.S. Department of Transportation (USDOT) has issued a number of similar fines to other carriers in recent years.

Volaris, which did not immediately respond to a request for comment, agreed to the penalty and told USDOT a series of events outside of its control combined to cause the tarmac delays and said it takes the rules seriously.

"This enforcement action reflects our ongoing commitment to protecting consumers and holding airlines accountable," Transportation Secretary Pete Buttigieg said in a statement.

USDOT in January 2023 said it planned to seek higher penalties from airlines and others that broke consumer protection rules, saying they were necessary to deter future violations.

In August, it fined American Airlines (NASDAQ:AAL) $4.1 million for unlawfully keeping thousands of passengers on the tarmac for hours, the largest-ever penalty for violating the rule.

American told the department the delays were the result of exceptional weather events, and that the 43 impacted flights represented less than 0.001% of the approximately 7.7 million flights operated.

In April 2023, USDOT imposed a $135,000 penalty on British Airways over a 2017 tarmac delay in which it failed to ensure the timely deplaning of passengers.