President Joe Biden speaks about the COVID-19 variant named omicron during a visit to the National Institutes of Health on Dec. 2, 2021, in Bethesda, Md. (Photo: AP)

Faced with a surging Omicron variant, US authorities will distribute 500 million free Covid-19 tests, mobilize military medical personnel if needed and increase vaccination capacity, a senior White House official said Tuesday.

"We have the tools to get through this wave," the official said, noting there are no plans to impose new restrictions. If Americans "are vaccinated and follow the precautions that we all know well, especially masking when traveling, they should feel comfortable celebrating Christmas and the holidays."