Japan extends a state of emergency until one month before the Olympics.

The Japanese government on Friday extended a state of emergency in Tokyo and eight other prefectures until at least June 20, barely one month before the city is scheduled to host the Olympic Games.

Although new coronavirus infections are declining, Japan is still recording more than 4,000 cases a day during a prolonged fourth wave that has strained medical systems in many cities. Officials said that it was necessary to continue restrictions on businesses that were enacted in April until the caseload drops further.

“The newly reported cases are on a downward trend, but they are still at a high level,” Yasutoshi Nishimura, a government minister who leads Japan’s Covid-19 response, said on Friday.

Under the emergency measures, restaurants, department stores and other major commercial businesses have been ordered to curtail their operating hours, and dining establishments are forbidden from serving alcohol.

Japan’s vaccine rollout has been among the slowest in the industrialized world, with only 2.4 percent of the population fully vaccinated, according to a New York Times database. This week, the country opened its first mass vaccination sites in an effort to jump-start inoculations. But the government’s current goals call for only those over 65 to be fully vaccinated by the end of July, when the Summer Games would have begun.

Amid frustration over the government’s response to the pandemic, public opposition to hosting the Olympics, which were postponed from last year, has grown. In a recent survey, 83 percent of Japanese people said that they did not want Tokyo to hold the Games. The daily Asahi Shimbun, an official Olympic partner, published an editorial this week calling on Japan’s prime minister, Yoshihide Suga, to cancel the Games.

But organizers and Japanese officials have insisted that the Games will go on. On Thursday, Toshiro Muto, chief executive of the Tokyo Olympics, said, “No one on the executive board has explicitly mentioned a view that we should cancel or postpone the Games,” adding that as coronavirus cases decline, public opinion “will improve.”