The Biden administration is tightening travel rules to and within the US, requiring all in-bound international passengers to test for COVID within 24 hours of departure starting on Monday.
It will also extend its mask requirement on planes and public transportation through March 18.
The changes were announced on Thursday as part of a broader plan to bolster the nation's arsenal of tools in its fight against the virus as the world enters its third year of the pandemic.
The plan is also the latest move by the Biden administration to stem the spread of the new, highly mutated omicron variant of the coronavirus.
Mr. Biden on Thursday said about 100 million Americans are eligible for booster shots and urged them to get the jab immediately.