Originally Published: 29 NOV 21 08:09 ET

Updated: 29 NOV 21 12:30 ET

By Kaitlan Collins and Kate Sullivan, CNN

(CNN) -- President Joe Biden on Monday said the new Omicron coronavirus variant is "a cause for concern, not a cause for panic," as federal health officials brace for the first cases of the new variant to be detected in the US.

"Sooner or later we're going to see cases of this new variant here in the United States. We'll have to face this new threat just as we face those who have come before it," Biden said, speaking from the White House.

The President noted scientists and officials are learning more every day about the new variant. He said the new travel restrictions his administration put in place, which went into effect Monday and restricted travel from several countries in Southern Africa, gives the US more time to respond.

Biden said the best protection against this new variant, as well as any other variants, is getting fully vaccinated against Covid-19 and getting a booster shot.

"We have the best vaccine in the world, the best medicines, the best scientists, and we're learning more every single day. And we'll fight this variant with scientific and knowledgeable actions and speed -- not chaos and confusion," Biden said.

He continued: "We have more tools today to fight the variant than we've ever had before, from vaccines to boosters to vaccines for children, 5 years and older and much more."

Officials briefed Biden for approximately 45 minutes Sunday on the new variant and again on Monday morning, with a heavy dose of caution about what's still unknown. Health officials say there are likely far more cases worldwide than is currently known.

Biden praised South African scientists for their transparency and quick work in identifying the new variant.

"This kind of transparency is to be encouraged and applauded because it increases our ability to respond quickly to any new threats, and that's exactly what we did," Biden said.

Biden's speech was expected to be more of a reassurance not to panic as scientists evaluate the threat than a specific update on the variant itself. He was expected to push Americans to get vaccinated against Covid-19 and promote booster shots for those who are already full vaccinated.

Biden's team told him it will likely take one to two weeks to know more about the variant, including whether antibodies handle it effectively. The US Centers for Disease Control and Prevention is currently sequencing coronavirus genomes and working closely with state health officials, two steps that will be critical to figuring out if the variant is already in the US.

Biden's chief medical adviser, Dr. Anthony Fauci, said Sunday that hopefully scientists will be able to make a determination soon on whether the Omicron variant is resistant to current Covid-19 vaccines. It's also too soon to tell whether Omicron causes more severe disease.

Fauci said he doesn't think there's any possibility that Omicron could completely evade any protection from the vaccine, but that it may diminish the level of protection.

If there is a diminution of protection, Fauci and other health officials said getting a Covid-19 vaccine booster shot could help enhance protection, since boosters enlarge the capacity of the body to recognize all kinds of mutations on coronavirus variants.

Vaccine maker Moderna's chief medical officer told CNN that the Omicron variant has at least 50 mutations -- including 30 on the key spike protein, which allows the virus to enter human cells, alone. He added that Omicron has thrown a "new wrench" into the fight against Covid-19, but emphasized that having some vaccination will help fight even a very altered and highly dangerous variant.

Biden announced Friday the US would restrict travel from South Africa and seven other countries starting Monday because of the new variant. The Biden administration is now restricting travel from South Africa, Botswana, Zimbabwe, Namibia, Lesotho, Eswatini, Mozambique and Malawi. The President was acting on advice from Fauci and the CDC.

The Omicron variant has already been detected on five continents -- North America, Australia, Africa, Europe, Asia -- and the travel restrictions are already generating push back, with South Africa's Ministry of International Relations and Cooperation saying they are "akin to punishing" South Africa.

The Omicron variant was the quickest to be labeled a "variant of concern" by the World Health Organization because of its seemingly fast spread in South Africa and its many troubling mutations.

WHO designates coronavirus variants as either variants of concern -- meaning they look dangerous enough to bear close scrutiny and continual updates -- or as variants of interest, or variants under monitoring. Only five currently meet the definition for variants of concern: Alpha, Beta, Gamma, Delta and Omicron.

This story has been updated with additional information.