The Tokyo metropolitan government reported 1,979 new daily COVID-19 cases on Thursday, a day before the Olympic ceremony and the highest number since mid-January, as fears grow that the games could become a superspreader event amid the transmission of the highly contagious Delta coronavirus variant.
The Olympic opening ceremony will be held on Friday without fans due to coronavirus restrictions in the capital, which is currently under a COVID-19 state of emergency declared amid surging infections.
In mid-January, Tokyo was under a second state of emergency.
The latest figure represents an increase of 671 from Thursday last week, bringing the seven-day rolling average of cases to 1,373.4 per day, up 55.7 percent from the previous week.
Health experts have warned of a possible "critical" coronavirus situation in Tokyo and that a "fifth wave" of infections is under way.
They have also estimated that daily infections could hit a record of around 2,600 in early August. The Olympics will run until Aug. 8.