The strain of the coronavirus pandemic on the health care system in Tokyo and other Japanese urban areas is reaching a critical phase, experts warned at a government meeting Wednesday, as the highly contagious Delta variant continued to drive the rise in the country's daily infections to a fresh record.

The number of new COVID-19 cases nationwide totaled 15,812 on Wednesday, topping the previous record of 15,753 reported on Saturday, according to a Kyodo News tally.

Experts at a meeting of the health ministry's pandemic response panel said the situation in Tokyo, currently under a fourth state of emergency, could deteriorate despite progress in getting people vaccinated.

Takaji Wakita, the head of the National Institute of Infectious Disease who chairs the panel, said the Tokyo Paralympics scheduled from Aug. 24 to Sept. 5 should be held without spectators like the Olympics which closed Sunday.

Tokyo's daily COVID-19 cases totaled 4,200 the same day, the Tokyo metropolitan government said, topping the 4,000 line again following a brief dip since late last week.

Its seven-day rolling average of new infections was 3,983.6 per day, up 14.5 percent from a week earlier. The cumulative total of confirmed coronavirus cases in Tokyo reached 258,981, the metropolitan government said.

Hiroshi Nishiura, professor of public health at Kyoto University, told the panel of the Ministry of Health, Labor and Welfare that, even in an optimistic scenario for the near-term pace of the coronavirus spread, all of about 6,000 beds which hospitals in Tokyo are prepared to provide for COVID-19 patients would be filled by the middle of this month.

By late August, nearly half of 400 beds secured for COVID-19 patients suffering severe symptoms would be taken up, Nishiura warned.

The number of patients showing severe symptoms in Tokyo rose to a fresh record of 197 on Wednesday from 176 the previous day, according to the metropolitan government.

The manager of one of the public health centers in Tokyo told the health ministry panel that the number of elderly people testing positive for the coronavirus has been rising recently despite most of them having been vaccinated, suggesting the country's vaccination program "is reaching its limit" in slowing the pandemic.