• The United States will begin requiring people flying in from the U.K. to test negative for Covid-19 no more than 72 hours before departure, the CDC said in a late Thursday statement.
• The CDC said President Donald Trump will sign the order on Friday and the measure will go into effect starting Monday.
• The announcement comes after the U.K. earlier this week said it identified a new strain of Covid-19 that appears to spread more quickly.

The United States will begin requiring people flying in from the U.K. to test negative for Covid-19 no more than 72 hours before departure, the CDC said in a late Thursday statement.

The announcement comes after the U.K. earlier this week said it identified a new strain of Covid-19 that appears to spread more quickly. The CDC said President Donald Trump will sign the order on Friday and the measure will go into effect Monday.

The CDC said passengers would have to provide airlines with documentation of their lab results from either polymerase chain reaction (PCR) or antigen tests.

Airlines, which have largely already announced such measures this week, would also have to confirm that passengers have tested negative before boarding, the agency said. They would also have to block passengers from boarding if they refuse to take a test.

Earlier this week, Delta Air Lines, Virgin Atlantic and British Airways began requiring passengers to test negative before boarding flights bound for New York's John F. Kennedy International Airport. United Airlines on Thursday said it would start requiring negative test results for passengers flying from London Heathrow to its hubs in Newark, New Jersey, Washington D.C., or Chicago starting Dec. 28.

Delta on Thursday extended the requirement on flights from London to Atlanta.

Airlines have drastically reduced service between the U.S. and the U.K. during the pandemic as travel restrictions and concerns about the virus have decimated demand.

United has four daily flights between the U.S. and Britain this month and plans to drop that number to two in January. Last winter, it operated 20 daily flights between the two countries, 18 of them to and from London Heathrow. On Monday, the airline said it would waive change fees, including fare differences, for travelers who want to change their London flights.

Delta is operating two flights a day between the U.S. and London this month, down from eight daily flights a year ago.

American Airlines has one flight a day between London and Dallas/Fort Worth International Airport, after slashing most of its December service to the U.K. last month due to weak demand.

The new strain spurred dozens of countries to swiftly restrict travel from the U.K. in efforts to prevent the strain from entering their own borders. The U.S. had already restricted travel from the U.K. in March, barring foreigners who had been in the country in the past two weeks.

The World Health Organization said, however, the new variant has also been detected in Australia, Denmark, Italy, Iceland and the Netherlands.

Earlier this week, the CDC suggested the new strain could already be circulating in the U.S. undetected. While the variant has not yet been found in the country, the CDC noted that the U.S. has only sequenced a fraction of Covid infections.