Prime Minister Fumio Kishida said Thursday that there are "signs of a resurgence" in coronavirus infections in Japan, particularly among young people.

Speaking to reporters, Kishida called for the public to cooperate in stemming the spread of the virus by taking thorough prevention measures, actively testing and receiving COVID-19 vaccine booster shots as early as possible.

Tokyo on Thursday reported 8,753 new infections, an increase of 527 from a week earlier. Those in their 20s accounted for 22.5 percent of the cases, the highest among all age groups.

At a meeting held the same day, the metropolitan government said the ratio of new infections for those in their 20s has risen in the week through Monday for the third consecutive week of increase, and was also the highest among all age groups.

With the vaccination rate for booster shots remaining low at 44.4 percent of the population in Tokyo, experts have cautioned that another resurgence of infections may be around the corner.

Norio Omagari, head of the Disease Control and Prevention Center at the National Center for Global Health and Medicine, said at the meeting that a rapid spread of the virus among those in their 20s has been seen "many times before" and urged that measures be taken now to avoid it triggering a "seventh wave."