The The american president told reporters his decision to restrict travel from southern African countries “gives us time” to take more action.
The new variant was originally reported to the World Health Organization (WHO) by South African scientists last Wednesday.
Follow the COVID update live across the UK and around the world
“Sooner or later we’ll see cases of this new variant in the United States,” Biden said.
“It’s a cause of worry, not a cause of panic… We will also fight and beat this new variant. “
“We are throwing everything we have on this virus,” the president said.
Mr Biden urged people to get the full shot – and those who can get booster shots. There are approximately 80 million unvaccinated Americans aged five and over.
He added: “We do not yet believe that further measures will be necessary”.
“If people are vaccinated and wear their masks, there is no need for containment. “
Mr Biden said it would be weeks before the world knew how effective the current vaccines would be against him.
Earlier, the WHO informed its 194 member countries that any increase in infections could have serious consequences, but said no deaths have yet been linked to the new variant.
Follow the Daily podcast on Podcasts Apple, Google Podcasts, Spotify, Streamer
“Omicron has an unprecedented number of cutting edge mutations, some of which are of concern for their potential impact on the trajectory of the pandemic,” said a statement.
“The overall overall risk associated with the new variant of concern Omicron is assessed as very high. “
More research was needed to understand Omicron’s potential to evade protection against vaccine-induced immunity and past infections, he said.