- The Netherlands confirmed 13 cases of the new omicron variant of the coronavirus on Sunday and Australia found two cases.
- The countries, half a world apart, became the latest to detect it in travelers arriving from southern Africa.
- A raft of curbs being imposed by nations around the world as they scramble to slow the variant's spread also grew.
- Israel decided to bar entry to foreign nationals in the toughest restriction so far.
The omicron coronavirus variant kept spreading around the world on Sunday, with 13 cases found in the Netherlands and two each in Denmark and Australia even as more countries imposed travel restrictions to try to seal themselves off.
Dutch health authorities said the 13 cases of the variant were found among people on two flights from South Africa to Amsterdam on Friday.
Authorities had tested all of the more than 600 passengers on those two flights and had found 61 coronavirus cases, going on to test those for the new variant.
"It is not unlikely more cases will appear in the Netherlands," Health Minister Hugo de Jonge told a news conference in Rotterdam. "This could possibly be the tip of the iceberg."
The discovery of Omicron, dubbed a "variant of concern" last week by the World Health Organization, has caused worry around the world that it could resist vaccinations and prolong the nearly two-year Covid-19 pandemic.
First discovered in South Africa, it has now been detected in Britain, Germany, Italy, the Netherlands, Denmark, Belgium, Botswana, Israel, Australia and Hong Kong.
Omicron is potentially more contagious than previous variants, although experts do not know yet if it will cause more or less severe Covid-19 compared to other strains.
Many countries have imposed travel bans or curbs on southern Africa to try to stem the spread. Financial markets dived on Friday as investors worried that the variant could stall a global recovery. Oil prices tumbled by about $10 a barrel.
Most Gulf stock markets ended lower on Sunday, with the Saudi and Dubai indexes suffering their biggest single-day fall in nearly two years.
In new cases detected on Sunday, Denmark said it had registered two cases in travelers from South Africa, while officials in Australia said two passengers who arrived in Sydney from southern Africa had tested positive for the variant.
Austria was investigating a suspected case and in France Health Minister Olivier Veran said the variant was probably already circulating there.
In the most far-reaching effort to keep the variant at bay, Israel announced late on Saturday it would ban the entry of all foreigners and reintroduce counter-terrorism phone-tracking technology to contain the spread of the variant.
Prime Minister Naftali Bennett said the ban, pending government approval, would last 14 days. Officials hope that within that period there will be more information on how effective vaccines are against Omicron.
The top U.S. infectious disease official, Anthony Fauci, said Americans should be prepared to fight the spread of the new variant, but it is too soon to say what actions are needed, including possible mandates or lockdowns.
In Britain, where two linked cases of Omicron identified on Saturday were connected to travel to southern Africa, the government announced measures to try to contain the spread, including stricter testing rules for people arriving in the country and requiring mask-wearing in some settings.
British health minister Sajid Javid said on Sunday he expected to receive advice imminently on whether the government can broaden a program of providing booster shots to fully vaccinated people, to try to weaken the impact of the variant.
Zhong Nanshan, a Chinese respiratory disease expert, said it could take some time to reach a conclusion on the harmfulness of the new variant, state television reported on Sunday.
Although epidemiologists say travel curbs may be too late to stop Omicron from circulating, many countries — including the United States, Brazil, Canada, European Union nations, Australia, Japan, South Korea and Thailand — have announced bans or restrictions on travel from South Africa and other southern African nations.
More countries imposed such curbs on Sunday, including Indonesia and Saudi Arabia.
The South African government has denounced the travel measures as unfair and potentially harmful to its economy, saying it is being punished for its scientific ability to identify coronavirus variants early.
Mexico's deputy health secretary, Hugo Lopez Gatell, said travel restrictions are of little use, calling measures taken by some countries "disproportionate."
"It (omicron) has not been shown to be more virulent or to evade the immune response induced by vaccines. They affect the economy and well-being of people," he said on Saturday.
Omicron has emerged as many countries in Europe are already battling a surge in Covid-19 infections, with some reintroducing restrictions on social activity to try to stop the spread.
The new variant has also thrown a spotlight on huge disparities in vaccination rates around the globe. Even as many developed countries are giving third-dose boosters, less than 7% of people in poorer countries have received their first Covid-19 shot, according to medical and human rights groups.
Seth Berkley, CEO of the GAVI Vaccine Alliance that with the WHO co-leads the COVAX initiative to push for equitable distribution of vaccines, said this was essential to ward off the emergence of more coronavirus variants.
"While we still need to know more about omicron, we do know that as long as large portions of the world's population are unvaccinated, variants will continue to appear, and the pandemic will continue to be prolonged," he told Reuters on Saturday.