Japanese infectious disease researchers say they have isolated the new strain of the coronavirus, which is contributing to a spike in the number of new cases in Britain.
The variant, which began spreading mainly from Britain, is estimated to be up to 70 percent more contagious.
It has also been detected in 20 people in Japan, including returnees from Britain and those related to them.
The National Institute of Infectious Diseases says the variant was isolated from samples taken from people who tested positive at airport quarantine checks in December.
The researchers analyzed the samples' genes and confirmed they were the same as those of the variant now rampant in Britain.
They also released an electron microscope image of the variant.
The institute plans to provide the isolated variant to other facilities in the country and abroad so they can study how its transmissibility and pathogenicity differ from the previously circulating forms of the virus.
Another variant was also detected in South Africa and elsewhere.
The institute says it aims to develop technology that will enable swift detection of variants and establish a monitoring system.