US Secretary of Transportation Pete Buttigieg on Wednesday blamed the recent mass flight cancellations on Southwest Airlines, calling it a “system failure”.

“We are past the point where they could say that this is a weather driven issue,” Buttigieg said in an interview with ABC News. "Don't get me wrong, all of this began with that severe storm. We saw winter weather affecting the country and severely disrupting all airlines.”

Buttigieg said flight cancellation rates were much higher when it comes to Southwest Airlines.

“So what this indicates is a system failure (at Southwest), and they need to make sure that these stranded passengers get to where they need to go,” he said.

Southwest has canceled more than 15,000 US-related flights since Dec. 22, including 2,509 flights canceled for Thursday, according to the flight tracking website FlightAware.

As thousands of Americans were stranded at the airports, President Joe Biden Tuesday said his administration will hold airlines accountable.

“Thousands of flights nationwide have been canceled around the holidays. Our Administration is working to ensure airlines are held accountable,” he tweeted. (Anadolu Agency)

•PHOTO:Secretary of Transportation blames cancellations on Southwest Airlines as passengers stranded at airports.