A new variant of Covid-19 has been detected in Japan.
91 cases of the mutation have been found in the Kanto area of eastern Japan, with two cases detected at airports.
The Tokyo Government has increased surveillance for new Covid variants.
Chief Cabinet Secretary Katsunobu Kato said: "It may be more contagious than conventional strains, and if it continues to spread domestically, it could lead to a rapid rise in cases."
Japan's National Institute of Infectious Diseases says it appears the variant, which has the E484K mutation, originated outside their country.
E484K makes it easier for Covid to spread and makes it more resistant to vaccines and immunity.
