Infections with the Omicron variant of the coronavirus have soared in the United States, leading to flight cancellations due to staff shortages amid the Christmas holiday season.

The Centers for Disease Control and Prevention said as of Sunday, the country's weekly average of new daily COVID-19 cases exceeded 206,500. Infections are surging particularly in the eastern and midwestern states. In the state of New York, the daily tally of new cases hit a record high of 49,708 on Friday.

People formed long lines as they waited to undergo virus tests in New York City on Monday. One person said he was being tested as a precaution before meeting his father even though he had already been given a booster shot.

US media outlets reported that over 3,000 flights were canceled during the Christmas holiday weekend.

Some of the cancellations were due to bad weather, but others were blamed on staff shortages after pilots and cabin crew were infected with the virus or were forced to quarantine.

The CDC said it is conducting investigations of about 70 cruise ships on which cases of infection have been reported.