BERLIN — A growing list of European Union nations were banning travel from the U.K. on Sunday and others were considering similar action,ina bidtoblocka new strain of coronavirus sweeping across southern England from spreading to the continent.

France, Germany, Italy, the Netherlands, Belgium, Austria, Ireland and Bulgaria all announced restrictions on U.K. travel, hours after British Prime Minister Boris Johnson announced that Christmas shopping and gatherings in southern England must be canceled because of rapidly spreading infections blamed on the new coronavirus variant.

Johnson immediately placed those regions under a strict new Tier 4 restriction level, upending Christmas plans for millions.

France banned all travel from the U.K. for 48 hours from midnight Sunday, and officials said that would buy time to find a “common doctrine” on how to deal with the threat. They specified that “flows of people or transport to the U.K. are not affected.”

Germany said all flights coming from Britain, except cargo flights, were no longer allowed to land starting midnight Sunday. It didn’t immediately say how long the flight ban would last.

Belgian Prime Minister Alexander De Croo said he was issuing a flight ban for 24 hoursstartingat midnight “out of precaution.” Belgium also halted train links to Britain, including the Eurostar.

“There are a great many questions about this new mutation,” he said, adding he hoped to have more clarity by Tuesday.

Johnson said Saturday that a fast-moving new variant of the virus that is 70% more transmissible than existing strains appeared to be driving the rapid spread of new infections in London and southern England in recent weeks. But he stressed“there’s no evidence to suggest it is more lethal or causes more severe illness,” or that vaccines will be less effective against it.

On Sunday, British Health Secretary Matt Hancock added to the alarm when he said “the new variant is out of control.” The U.K. recorded 35,928 further confirmed cases, around double the number from a week ago.

Germany, which holds the rotating EU presidency, called a special crisis meeting on Monday to coordinate the response to the virus news among the bloc’s 27 member states.

The Netherlands banned flights from the U.K. for at least the rest of the year.

Ireland issued a 48-hour flight ban. Italy said it would block flights from the U.K. until Jan.6, and an order signed Sunday prohibits entry into Italy by anyone who has been in the U.K. in the last 14 days.

The Czech Republic imposed stricter quarantine measures from people arriving from Britain.

High-speed train operator Eurostar canceled its trains between London, Brussels and Amsterdam beginning Monday, but kept trains operating on the Londonto-Paris route.

Beyond Europe, Israel also said it was banning flights from Britain, Denmark and South Africa because those were the countries where the mutation is found.

The World Health Organization tweeted late Saturday that it was “in close contact with U.K. officials on the new #COVID19 virus variant” and promised to update People wait to board the last train to Paris on Sunday at the St Pancras railway station in London. Several nations in the EU opted to ban travel from the U.K. amid a surge of cases resulting from a more virulent coronavirus strain. STEFAN ROUSSEAU/PA governments and the public as more is learned.

The new strain was identified in southeastern England in September and has been spreading in the area ever since, a WHO official told the BBC on Sunday.

“What we understand is that it does have increased transmissibility, in terms of its ability to spread,” said Maria Van Kerkhove, WHO’s technical lead on COVID-19.

Studies are under way to better understand how fast it spreads and whether “it’s related to the variant itself, or a combination of factors with behavior,” she added.

Shesaidthestrainhadalso been identified in Denmark, the Netherlands and Australia,wheretherewasonecase that didn’t spread further.

“The longer this virus spreads, the more opportunities it has to change,” she said. “So we reallyneed to do everything we can right now to prevent spread.”

Viruses mutate regularly, and scientists have found thousands of different mutations among samples of the virus causing COVID-19.

Many of these changes have no effect on how easily the virus spreads or how severe symptoms are.

British health authorities said that while the variant has been circulating since September, it wasn’t until the last week that officials felt they had enough evidence to declare that it has higher transmissibility than other circulating coronaviruses.