Japan was on high alert Friday due to the rising number of confirmed COVID-19 cases nationwide, including that of two taxi drivers and a doctor, as well as the nation's first death blamed on the virus.

The latest cases bring the number of people who have tested positive in Japan, excluding cases from the Diamond Princess cruise ship in Yokohama, to at least 39.

The health ministry launched a full-scale investigation into the route of the fatal infection of a Kanagawa Prefecture woman because the case suggests the possibility that it was transmitted domestically.