Southwest Airlines Co. on Tuesday came under fire from the U.S. government after the low-cost carrier kept canceling flights due to harsh winter weather that grounded planes and disrupted holiday travel.

U.S. airlines have canceled thousands of flights as an arctic blast and a massive winter storm swept over much of the country before the Christmas holiday weekend.

President Joe Biden said his administration was working to ensure airlines were "held accountable," according to a tweet on his official POTUS handle.

Many carriers were limping back to normalcy on Tuesday, when tracking website FlightAware showed that Dallas-based Southwest accounted for 86 percent of all U.S. airline cancellations.

The carrier, which typically has an aggressive schedule that connects vast swathes of the country, has scrapped more than 12,000 flights since Friday. It said on Tuesday it would operate roughly a third of daily flights for the next several days.

Other government officials including U.S. Transportation Secretary Peter Buttigieg termed Southwest's cancellations "unacceptable."

Buttigieg spoke with Southwest Airlines Chief Executive Bob Jordan on Tuesday and pressed the airlines on refunds, a department spokesperson said, adding the department would take action to hold Southwest accountable if it failed to fulfill its obligations.

Democratic Representative Colin Allred criticized the "catastrophic collapse" of Southwest's flight schedule. U.S. Senate Commerce, Science, and Transportation Committee Chair Maria Cantwell said Southwest's problems "go beyond weather," and the committee would look into causes and impact of these disruptions.

(Cover: The arrivals board shows cancelled flights at the Southwest Airlines Baggage Claim at Midway Airport in Chicago, Illinois, U.S., December 27, 2022. /CFP)