The Tokyo metropolitan government reported 1,308 new coronavirus cases on Thursday, the most since Jan. 21, as health experts warned infections could surge to 2,000 a day shortly after the Olympics end in early August.
The figure topped 1,000 for the second day in a row as the capital prepares to host the games in just over a week while under a fourth COVID-19 state of emergency.
New cases in Tokyo topped the week-earlier figure for the 26th straight day, bringing its seven-day moving average of infections to 882.1 per day, up 32.9 percent from the previous week.
The moving average could jump to 2,406 by Aug. 11 if the coronavirus continues to spread at the current pace, health experts advising the metropolitan government said, eclipsing the third wave that swept across Tokyo in the winter.
The metropolitan government confirmed four deaths Thursday.
The Olympics opening ceremony is set to take place at the National Stadium on July 23 amid concerns that the games, coupled with the highly contagious Delta variant of the coronavirus, could become a superspreader event.
Organizers have promised adequate steps to ensure the tens of thousands of athletes, staff and members of the media arriving in Japan will not spread COVID-19, including preventing them from coming into contact with the public.
Prime Minister Yoshihide Suga on Thursday visited Narita airport near Tokyo and was briefed on the measures, telling reporters, "It is the responsibility of the government, which is tasked with protecting the lives of the Japanese people, to ensure proper border controls are in place."