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.


Trump cancels US strikes on Iran, citing progress in talks
US confirms third strike on Indian-crewed tankers this week
UK defence minister Healey quits, says PM Starmer's plans fail to keep country safe
False alarm at the Pentagon triggers brief shelter-in-place order
Trump says US will hit Iran 'very hard', take control of energy infrastructure
US and Iran trade attacks for a second day, undermining shaky ceasefire
Bahrain says debris from intercepted Iranian drones injures child, damages homes
Philippines launches probe into deaths of two athletes from top basketball team
