BERLIN (AP) — The Netherlands, Belgium and Austria on Sunday banned flights from the U.K. and Germany considered limiting such flights to make sure that a new strain of coronavirus sweeping across southern England does not establish a strong foothold on the continent.

The Netherlands banned flights from the U.K. for at least the rest of the year while Belgium issued a flight ban for 24 hours starting at midnight and also halted train links to Britain, including the Eurostar. German officials were considering “serious options” regarding incoming flights from the U.K., but have not yet taken action.

Austria said it would also halt flights from the U.K. but there were no immediate details on the timing of the ban, the Austrian news agency APA reported. The Czech Republic, meanwhile, imposed stricter quarantine measures from people arriving from the U.K.

The five EU governments say their response comes in reaction to tougher measures imposed Saturday in London and surrounding areas by British Prime Minister Boris Johnson. He immediately put those regions into a new Tier 4 level of restrictions, saying that a fast-moving new variant of the virus that is 70% more transmissible than existing strains appears to be driving the rapid spread of new infections in London and southern England.

“There’s no evidence to suggest it is more lethal or causes more severe illness,” Johnson said, or that vaccines will be less effective against it.

Belgian Prime Minister Alexander De Croo said Sunday said he was issuing the flight ban for 24 hours starting at midnight “out of precaution.”

“There are a great many questions about this new mutation and if it is not already on the mainland,” he said. He hoped to have more clarity by Tuesday.

The World Health Organization tweeted late Saturday that, “We're in close contact with U.K. officials on the new #COVID19 virus variant." It promised to update governments and the public as more is learned about this variant.

The new strain of coronavirus was identified in southeastern England in September and has been circulating in the area 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 and whether “it’s related to the variant itself, or a combination of factors with behavior,” she said.

She said the strain had also been identified in Denmark, the Netherlands and Australia, where there was one case that did not spread further.

“The longer this virus spreads, the more opportunities it has to change,” she said. “So we really need to do everything we can right now to prevent spread, and minimizing that spread will reduce the chances of it changing.”

Susan Hopkins of Public Health England said that while the variant has been circulating since September, it wasn’t until this week that officials felt they had enough evidence to declare that it has higher transmissibility than other circulating viruses.

The strain has spread to other parts of the U.K. but in smaller amounts than in London and surrounding areas, she told the BBC.

Germany has not yet spelled out a ban but is considering limiting or halting flights from the U.K. as well, the dpa news agency reported Sunday. A high-ranking German official told dpa that restrictions on flights from Britain are a “serious option.”

The Czech Republic announced that all people arriving in the country who spent at least 24 hours on British territory during the last two weeks have to isolate as of this Sunday.

Germany, which holds the rotating presidency of the 27-nation EU, was in contact with its neighbors and was following all developments about the new variant closely, dpa reported.

Europe has been walloped this fall by soaring new infections and deaths due to a resurgence of the virus, and many nations have reimposed a series of restrictions to reign in their outbreaks.

Britain has seen over 67,000 deaths in the pandemic, the second-highest confirmed toll in Europe after Italy.

Johnson on Saturday closed all non-essential shops, hairdressers, gyms and pools and told Britons to reorganize their holiday plans. No mixing of households is now allowed indoors in Tier 4 areas, including London, and only essential travel is permitted into and out of such areas. In the rest of England, people will be allowed to meet in Christmas bubbles for just one day instead of the five that were planned.

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Raf Casert in Brussels, Sylvia Hui in London and Karel Janicek in Prague contributed reporting.