The new coronavirus infection count has been rising across the nation with more than 200 cases reported in Tokyo on Sunday.
Metropolitan government officials say 206 new cases were confirmed in the capital. That makes it the fourth day in a row the figure has topped 200.
Infections are also rising in the western city of Osaka. The prefectural government says 32 people were confirmed infected on Sunday. In 21 of those cases, the route of infection was unclear.
The prefecture has decided to issue an alert based on its own criteria, called the "Osaka model."
Osaka Governor Yoshimura Hirofumi said, "It's becoming clear that infections are spreading among young people through the nightlife business. We aim to take firm measures to target the epicenter."
And in the southern island prefecture of Okinawa, the government says the US military has informed it of a new case at the Makiminato Service Area.
That brings the number of cases among people connected to the US military to 66.
Across Japan, there were over 400 new cases confirmed on Sunday. That brings the total to about 22,000.