The World Health Organization said Friday a new coronavirus strain detected in South Africa is a highly transmissible "variant of concern" and named it "Omicron."

The emergence of the B.1.1.529 variant, first reported to the WHO from South Africa on Wednesday, has caused authorities around the world to react with alarm and led them to quickly tighten travel restrictions.

Photo taken on Feb. 14, 2020, shows the headquarters of the World Health Organization in Geneva. (Kyodo)

An advisory panel of the U.N. health agency has warned the variant has "a large number of mutations, some of which are concerning."

Compared with other variants, preliminary evidence has found an "increased risk of reinfection" with Omicron, the WHO said, adding the new variant can be detected by current PCR diagnostics.

The new variant has already been confirmed outside South Africa, including Hong Kong, Belgium and Israel.

According to Japan's National Institute of Infectious Diseases, the Omicron variant has 32 mutations in the spike protein, which may allow it to more easily enter the body's cells.

With the discovery of the new variant, the World Trade Organization on Friday decided to indefinitely postpone its ministerial meeting set to open next week after Switzerland tightened entry restrictions.

The four-day meeting was scheduled to open Tuesday at the WTO headquarters in Geneva to discuss issues including how to curb export restrictions on medical goods. It would have been the world trade body's first ministerial talks in four years.

From Japan, Foreign Minister Yoshimasa Hayashi and trade minister Koichi Hagiuda were both planning to attend.

The WTO said its General Council agreed late Friday to postpone the meeting after Switzerland banned direct flights from South Africa and six other southern African countries.

"Given these unfortunate developments and the uncertainty that they cause, we see no alternative but to propose to postpone the ministerial conference and reconvene it as soon as possible when conditions allow," the WTO quoted Dacio Castillo, a Honduran ambassador and chair of the council, as saying.

The WTO, which has 164 members representing 98 percent of world trade, normally convenes a ministerial conference every two years. The meeting that was originally due to take place in Kazakhstan in June 2020 was put off also due to the coronavirus pandemic.