The White House is "actively looking" into the possibility of requiring passengers to submit to COVID-19 tests before boarding domestic flights, ABC News reports.

Senior official with the Centers for Disease Control and Prevention, Marty Cetron, told ABC News, "These are conversations that are ongoing, and looking at what the types and locations of testing might be. We’re actively looking at it."

This would be an extension of the administration's requirement that U.S.- bound travelers submit to testing, which went into effect on Tuesday (Jan. 26). Under the new mandate, all travelers flying into the U.S. must provide proof of a negative COVID-19 test, taken no more than three days before their flight, or they will be denied boarding.

The order was initially announced by the CDC on Jan. 12 and formalized in an executive order President Joe Biden signed last week.

"We urge folks to postpone their trips if they're able," acting Assistant Secretary of Consular Affairs Ian Brownlee said Tuesday, "and if they absolutely must travel to equip themselves with information."

Acording to ABC News, Brownlee warned that travelers will be responsible for covering their own lodging and medical costs if they test positive or cannot get a test while overseas.

"The bottom line message is this is really not a time for people to be engaging in discretionary travel, and that all travel should be postponed until we get a better handle on getting this virus under control and accelerate our vaccination strategies," Cetron said.