The World Health Organization (WHO) warned on Monday that the Omicron variant of the coronavirus poses "a very high risk" to the world and could trigger new waves of infections with "severe consequences".

The UN health agency's assessment made public in Geneva is the gravest warning yet by the entity yet about the strain identified a few days ago by researchers in South Africa.

The WHO said that there are still "considerable unknowns" about the Omicron variant, but that preliminary evidence points to the possibility that some of its many mutations allow it to evade immune system response and increase its ability to be transmitted from one person to another.

In the case of Argentina, direct flights from African countries have been suspended. Also, travelers who have had a trip through that continent must take a PCR test and comply with a mandatory 14-day quarantine upon arrival.