France announced that it has implemented a 48-hour ban on travel to Britain, joining a growing number of European countries halting travel to Britain after a new strain of the coronavirus was detected in that country. At least six European countries have announced flights will cease if they haven’t done so already, while France and Belgium have banned train travel.

French officials said the 48-hour stoppage would give them time to find a “common doctrine” to stop the spread of the new COVID-19 variant.

Germany, which holds the EU presidency, called a special crisis meeting for Monday to coordinate a response. Canada also announced U.K. travel restrictions. Prime Minister Justin Trudeau said all flights from the U.K. would be “prohibited from entering Canada” for 72 hours. The travel ban does not affect cargo shipments.

Top health officials in Britain say a new, fast-moving variant of the coronavirus could be up to 70% more transmissible than previous ones. This strain appears to be driving the rapid spread in London and southern England. But there is no evidence the new strain is deadlier or would react differently to the vaccine.

As a result of the new strain, Prime Minister Boris Johnson announced a new tier of coronavirus restrictions, the strictest yet, and canceled the planned five-day Christmas relaxation period that had been planned from December 23 through 27.