TOKYO — North Korea said Tuesday it will not send a team to the Tokyo Olympics, citing the need to protect its athletes from the coronavirus, as concerns about the viability and safety of the massive sporting event continue to grow.

The Sports Ministry’s announcement makes North Korea the first country to withdraw from the already-delayed Games, which are scheduled to open in July. The decision largely reflects North Korea’s extraordinary determination to keep the virus out; the country has imposed severe border restrictions and officially claims to be virus-free.

But North Korea may not be the last nation to withdraw from the blighted Summer Olympics amid an explosion in cases of dangerous variants within Japan and an extremely slow domestic vaccination campaign.

The decision came at a meeting of North Korea’s Olympic committee March 25, the ministry said on its Joson Sports website. “The committee decided not to join the 32nd Olympic Games to protect athletes from the global health crisis caused by the coronavirus,” it said.

North Korea won two gold, three silver and two bronze medals at the Rio de Janeiro Olympics in 2016, mainly in weightlifting, so its withdrawal could affect the medals table. But it also dashes the South Korean government’s hopes that the Olympics might present an opportunity to resume dialogue with the isolated regime, as the Winter Games were three years ago.

Athletes from North and South Korea marched together under a united flag at the Opening Ceremonies of the 2018 Winter Olympics in PyeongChang, South Korea, while the delegation from the North included Kim Yo Jong, younger sister of the country’s ruler, Kim Jong Un.

These days, though, North Korea is not talking to Seoul or Washington, and any hopes of an Olympic thaw were probably unrealistic.

Pyongyang’s withdrawal reflects its paranoia about the pandemic. The country throttled its trade lifeline by closing its border with China early last year, at huge economic and humanitarian cost.

But the decision to withdraw sets a worrying precedent for the Games, just as concerns grow about sending athletes to Japan.

Last week, FINA, the international water-sports governing body, canceled the Diving World Cup, an Olympic-qualifying event that had been due to take place in Tokyo this month, citing “a very negative opinion” from its experts about organizers’ plans to contain the virus.

“In their view, this plan will not properly ensure health and protection guarantees to participants,” FINA wrote in a letter to national federations, the BBC reported.

Gymnastics and artistic swimming test events due to take place in May have also been called off, partly because of travel restrictions on international participants and officials, while a water polo test event next week has been canceled, according to media reports.

The torch relay, which began last month in low-key fashion, is set to be rerouted away from the western city of Osaka, after the local government asked that the leg be canceled because of a surge in coronavirus cases there.

Osaka and the nearby city of Kobe have become a hotbed of cases for the virus variant first found in Britain, which account for about half of recently detected cases in those cities, while Tokyo has seen a rise in cases with the E484K mutation found in the variants first identified in South Africa and Brazil. The “eek” mutation is thought to make vaccines slightly less effective.

On Sunday, a Tokyo hospital announced that of 14 people it had tested for the virus last month, 10 had the dangerous “eek” mutation, and television tallies show that more than 1,000 people nationwide have been found to have different virus variants.

Japan has delivered just 1.2 million doses of the coronavirus vaccine jointly developed by U.S. pharmaceutical firm Pfizer and German biotech company BioNTech, almost all to health workers. That’s less than one dose per 100 people, one of the slowest rollouts among developed nations. The Health Ministry, which takes a cautious approach to vaccines, has yet to approve any other coronavirus vaccines for use. The United States has authorized three coronavirus vaccines for emergency use.

The Games have been postponed by a year, and last month, organizers decided to ban spectators from overseas. Opinion polls show most people in Japan oppose hosting the Olympics this summer.

Min Joo Kim in Seoul and Julia Mio Inuma in Tokyo contributed to this report.