Health officials in Tokyo have appealed for more than 800 theatregoers to get tested for COVID-19 after a stage production was found to be the source of at least 20 new cases.
The government said it was focusing on a 190-seat theatre in the Shinjuku entertainment district.
The venue staged a play for six days starring mainly up-and-coming boy-band members earlier this month.
All 800 spectators who went to see the performance have been identified as high-risk contacts.
Authorities came to know of the first infection among a cast member on July 6, while subsequent tests found at least 20 related cases.
Tokyo reported 119 new COVID-19 infections on Monday after a period of four days when the daily tally exceeded 200.


Russia says Ukrainian drone hit engineers around Zaporizhzhia nuclear plant
US judge invalidates Trump policies targeting immigrants from 39 countries
NASA reverses evacuation alert order for astronauts aboard space station
WHO announces $518 million six-month plan to fight Ebola
Trump says he does not need deal with Iran to get enriched uranium