WASHINGTON -- The US Centers for Disease Control and Prevention (CDC) announced on Tuesday a new requirement for a negative COVID-19 test to all air passengers entering the United States.

The new order, signed by CDC Director Robert Redfield Tuesday, will become effective on Jan. 26.

"Testing before and after travel is a critical layer to slow the introduction and spread of COVID-19. This strategy is consistent with the current phase of the pandemic and more efficiently protects the health of Americans," said a statement of the CDC.

Air passengers are required to get a viral test within the 3 days before their flight to the U.S. departs, and provide written documentation of their laboratory test result to the airline or provide documentation of having recovered from COVID-19.

Airlines must confirm the negative test result for all passengers or documentation of recovery before they board, the new order requires.