Japan has detected a coronavirus variant found in South Africa, the government said, the first such discovery in a nation that has already identified more than a dozen cases of another variant that is spreading rapidly in Britain.

A woman in her 30s who arrived in Japan on Dec. 19 was found to be infected with the new virus variant, the health ministry said on Monday. South Africa's health authorities have said the variant might be responsible for a recent surge in infections there.

The announcement of the detection of the South Africa-linked variant comes after the Japanese government on Monday started banning the entry of nonresident foreign nationals following the discovery of the U.K. variant in Japan.