The sources said a formal announcement prolonging the demands through March 18 is expected on Thursday. The White House and the Transportation Security Administration (TSA) refused to disclose. The TSA in August extended the transportation mask order through Jan. 18.
The White House also wishes to announce harsh testing rules for international visitors. The U.S. Centers for Disease Control and Prevention (CDC) confirmed late on Tuesday it is working to impose stricter COVID-19 testing rules for air travelers entering the United States amid concerns about the Omicron variant.
The first known U.S. case of the Omicron variant was verified on Wednesday - a fully vaccinated person in California who returned to the United States from South Africa on Nov 22 and tested positive seven days later.
On Monday, the United States barred most foreign nationals who have been in eight southern African countries. The CDC told airlines late on Tuesday it would ask them to turn over passenger contact information for all travelers in those countries and deliver that to state and public health agencies.
The current CDC order, which has been intact since soon after Biden took office in January, demands masks to be worn by all travelers on airplanes, ships, trains, subways, buses, taxis, ride-shares. Masks are also required at all transportation hubs such as airports, bus or ferry terminals, train and subway stations, and seaports.
His forerunner, Donald Trump, rejected requests from U.S. public health agencies to implement the requirements in transit - even though airlines and some other transportation modes had asked for masks.
Government agencies briefed industry officials about the development late on Wednesday; sources told Reuters.
The mask requirements have been the source of conflict, especially aboard U.S. airlines, where some travelers have declined to wear masks.
The Federal Aviation Administration, which has instituted a "zero tolerance" enforcement effort on unruly passengers, said on Tuesday that since Jan 1, it had received reports from airlines of 3,923 passengers refusing to wear masks.
In some U.S. states, transportation centers are the only places where masks are still needed.
The White House has been weighing several reforms to strengthen international testing.
For now, vaccinated international air travelers can provide a negative test result received within three days from their point of embarkation. Nearly all foreign nationals must be vaccinated to enter the United States. Currently, unvaccinated travelers must get a negative COVID-19 test within one day of arrival.