Australian officials confirmed Sunday that two overseas travelers arriving in Sydney had tested positive for the omicron variant of the coronavirus, as nations around the world tightened controls against the worrying new strain.The two passengers were among a group of 14 others who arrived in Australia from southern Africa on Saturday, They were asymptomatic and were both vaccinated for COVID-19. The remaining 12 have been placed in quarantine.Neighboring New Zealand announced it was restricting travel from nine southern African countries because of the threat posed by the variant, and Japan widened its border controls to include more countries from the region. Tourist-dependent Thailand, which only recently began loosening its tight border restrictions to leisure travelers from certain countries, announced a ban of its own on visitors from eight African countries. Similar restrictions took effect in the business hub of Singapore, which is barring entry and transit to anyone with a recent history of travel to seven southern African nations. Sri Lanka banned disembarkation of passengers arriving from six African countries due to the detection of the omicron variant, as did the Maldives, the luxury Indian Ocean resort archipelago.Israel went further, barring entry to all foreign nationals, mandating quarantine for all Israelis arriving from abroad and red-listing travel to 50 African countries. It also approved use of the Shin Bet internal security agency's controversial phone monitoring technology to perform contact tracing of individuals confirmed with the new omicron variant of coronavirus in Israel.The tighter restrictions reflect steps rapidly taken by countries around the world to limit the spread of the omicron variant just days after it was identified by researchers in South Africa. The act first, ask questions later approach reflected growing alarm about the emergence of a potentially more contagious variant nearly two years into a pandemic that has killed more than 5 million people, upended lives and disrupted economies across the globe.While much remains to be learned about the new variant, researchers are concerned that it may be more resistant to the protection provided by vaccines and could mean that the pandemic lasts for longer than anticipated. Cases involving the omicron variant have already been confirmed on multiple continents, with Germany, Italy, Belgium, Israel and Hong Kong all reporting cases in recent days. The United States' top infectious diseases expert, Dr. Anthony Fauci, said he would not be surprised if the omicron variant was already in the U.S., too. "We have not detected it yet, but when you have a virus that is showing this degree of transmissibility ... it almost invariably is ultimately going to go essentially all over," Fauci said on NBC television.In Australia, the New South Wales health department said the infected travelers were from one of nine African countries that are now required to quarantine in a hotel upon arrival in Sydney. The countries are South Africa, Lesotho, Botswana, Zimbabwe, Mozambique, Namibia, Eswatini, Malawi and the Seychelles.New Zealand's COVID-19 Response Minister Chris Hipkins said the island nation was taking a precautionary approach. From late Sunday, only New Zealand citizens from nine African countries will be allowed entry to New Zealand, and they will be required to spend two weeks in a quarantine hotel run by the military. Hipkins said officials were confident the variant hadn't entered New Zealand and they were well placed to keep it out. Many countries have slapped restrictions on various southern African countries over the past couple of days, including Brazil, Canada, the European Union, Iran, and the U.S., in response to warnings over the transmissibility of the new variant. This goes against the advice of the World Health Organization, which has warned against any overreaction before the variant was thoroughly studied. —Associated Press writers Nick Perry in Wellington, New Zealand, Mari Yamaguchi in Tokyo, Krishan Francis in Colombo, Sri Lanka contributed to this report.

Britain became the latest country Saturday to report cases of the new potentially more contagious omicron variant of the coronavirus as world governments sought to shore up their defenses by slapping restrictions on travel from nations in southern Africa.U.K. Health Secretary Sajid Javid confirmed that two people have tested positive with the omicron variant in the southeastern English town of Chelmsford and in the central city of Nottingham. He said the cases were linked and related to travel from southern Africa.Video above: Expert on emergence of new COVID variantJavid said the two confirmed cases are self-isolating alongside their households while contact tracing and targeted testing take place. He also said arrivals from Angola, Malawi, Mozambique and Zambia will have to quarantine from Sunday and stressed the importance of booster jabs."This is a real reminder that this pandemic is far from over," he said. "If we need to take further action, we will."Prime Minister Boris Johnson, along with his top advisers, will be holding a media briefing later Saturday. Many countries have slapped restrictions on various African countries over the past couple of days including Australia, Brazil, Canada, the European Union, Iran, Japan, Thailand and the United States, in response to warnings over the transmissibility of the new variant — against the advice of the World Health Organization. Pharmaceutical companies expressed optimism that they could finesse their vaccines to deal with the new variant though that would clearly take some time.Despite the banning of flights, there are mounting concerns that the variant has already been widely seeded around the world. In addition to the U.K., cases have been reported in travelers in Belgium, Israel and Hong Kong. Germany also said it suspected a positive case and Dutch authorities were testing whether 61 people who arrived on two flights from South Africa with COVID-19 have the omicron variant. The planes arrived in the Netherlands from Johannesburg and Cape Town shortly after the Dutch government imposed a ban on flights from southern African nations. The 539 travelers who tested negative were allowed to return home or continue their journeys to other countries. Under government regulations, those who live in the Netherlands and are allowed to return home must self-isolate for at least five days.Meanwhile, a German official said that there's a "very high probability" that the omicron variant has already arrived in the country.Kai Klose, the health minister for Hesse state, which includes Frankfurt, said in a tweet that "several mutations typical of omicron" were found Friday night in a traveler returning from South Africa, who was isolated at home. Sequencing of the test had yet to be completed.The global health body has named the new variant omicron, labeling it a variant of concern because of its high number of mutations and some early evidence that it carries a higher degree of infection than other variants. That means people who contracted COVID-19 and recovered could be subject to catching it again. It could take weeks to know if current vaccines are less effective against it.With so much uncertainty about the omicron variant and scientists unlikely to flesh out their findings for a few weeks, countries around the world have been taking a safety-first approach, in the knowledge that previous outbreaks of the pandemic have been partly fueled by lax border policies.Nearly two years on since the start of the pandemic that has claimed more than 5 million lives around the world, countries are on high alert. The variant's swift spread among young people in South Africa has alarmed health professionals even though there was no immediate indication whether the variant causes more severe disease. In just two weeks, omicron has turned a period of low transmission in the country into one of rapid growth.A number of pharmaceutical firms, including AstraZeneca, Moderna, Novavax and Pfizer, said they have plans in place to adapt their vaccines in light of the emergence of omicron. Pfizer and its partner BioNTech said they expect to be able to tweak their vaccine in around 100 days.Professor Andrew Pollard, the director of the Oxford Vaccine Group which developed the AstraZeneca vaccine, expressed cautious optimism that existing vaccines could be effective at preventing serious disease from the omicron variant.He said most of the mutations appear to be in similar regions as those in other variants."That tells you that despite those mutations existing in other variants the vaccines have continued to prevent serious disease as we've moved through alpha, beta, gamma and delta," he told BBC radio. "At least from a speculative point of view we have some optimism that the vaccine should still work against a new variant for serious disease but really we need to wait several weeks to have that confirmed."He added that it is "extremely unlikely that a reboot of a pandemic in a vaccinated population like we saw last year is going to happen."Some experts said the variant's emergence illustrated how rich countries' hoarding of vaccines threatens to prolong the pandemic.Fewer than 6% of people in Africa have been fully immunized against COVID-19, and millions of health workers and vulnerable populations have yet to receive a single dose. Those conditions can speed up spread of the virus, offering more opportunities for it to evolve into a dangerous variant."One of the key factors to emergence of variants may well be low vaccination rates in parts of the world, and the WHO warning that none of us is safe until all of us are safe and should be heeded," said Peter Openshaw, a professor of experimental medicine at Imperial College London."Global vaccine rollout is vital," he added.___Pan Pylas contributed from London. Geir Moulson in Berlin contributed to this report.