Japan Prime Minister Yoshihide Suga was still uncertain whether fans can be allowed at the Tokyo Olympics because of growing concern about rising COVID-19 cases on Thursday only three weeks before the games.

Cases in Tokyo have been steadily on the rise, triggering fears the games would accelerate the spread of the coronavirus. Experts warn the highly contagious delta strain could trigger rapid resurgence of the infections that may require another state of emergency even during the games starting on July 23.

“I have made clear that having no spectators is a possibility,” Suga said as he noted Tokyo’s rising caseloads. “We will take steps as we prioritize safety and security of the people.”

Tokyo on Wednesday confirmed 673 new cases, the 12th straight day of a week-on-week increase.

Dr. Mitsuo Kaku, a medical advisor for the Tokyo metropolitan government, told a weekly meeting on Thursday that Tokyo is turning into a “critical situation” as the upsurge is triggered by the delta variant.