The bleak milestone underlines the severity of the situation in the Japanese capital as it grapples with a surge in cases - just seven months before it is due to stage the Games.

On Thursday (December 17), Tokyo reported a record 822 new cases in 24 hours as the city reached the fourth level of its COVID-19 alert system for the first time.

"Tokyo’s health care system is approaching capacity," said Tokyo Governor Yuriko Koike in an interview with Japan Times.

"Hospitals are clogged and could soon lose the ability to perform basic functions at a critical time of the year."

Tokyo has recorded almost 51,500 cases, resulting in more than 500 deaths since the start of the global health crisis.

Japan’s daily count for cases exceeded 2,000 for the fifth successive day yesterday, and the country’s overall death toll stands at 2,893.

"The virus is spreading at an increasing pace," said Norio Ohmagari, director of the Disease Control and Prevention Center during a meeting at the Tokyo Metropolitan Government.

"Stronger measures are necessary to prevent more people from becoming infected, and to prevent those infected from developing severe symptoms."

With five days to go until Christmas, many European countries have been forced to tighten restrictions and even impose nationwide lockdowns, with the situation there considerably worse than in Japan.

Yesterday, Chris Whitty, the United Kingdom Government's chief medical officer, warned a new variant of coronavirus had been found that was spreading more quickly.

With cases surging, Prime Minister Boris Johnson has decided against relaxing coronavirus rules over the festive period and instead put most of southern England - including London - into tier four, the highest level of restrictions.

Italy, The Netherlands and Germany have also imposed lockdowns until the new year, while Austria is set to make a similar move after Christmas.

French President Emmanuel Macron and Slovakian Prime Minister Igor Matovič recently tested positive for COVID-19 after attending a European Union summit in Belgian capital Brussels along with other leaders.

Following the outbreak of coronavirus, organisers agreed to postpone Tokyo 2020 to 2021 - the first time the Games have been moved since the Second World War.

It was announced earlier this month that the postponement is expected to cost the Organising Committee $2.8 billion (£2 billion/€2.3 billion).

The current situation across the world raises fresh concerns over Tokyo 2020, but officials including International Olympic Committee President Thomas Bach have previously pledged to stage a safe Games next summer.

Tokyo 2020 will reportedly spend $960 million (£720 million/€801 million) on COVID-19 countermeasures and are meeting regularly with the Japanese Government and Tokyo Metropolitan Government to formulate plans to combat the virus.

The wearing of face masks and social distancing are expected to be compulsory, while athletes will be encouraged to limit their stay in Japan after competition.

The Pfizer-BioNTech vaccine against coronavirus is currently being administered in the UK and the United States, and approval is pending in Japan.

Vaccines have also been developed by American company Moderna and the University of Oxford, raising hopes of a successful staging of Tokyo 2020, although how quickly they can be rolled out and what impact this will have on transmission rates remains to be seen.

Ethical questions regarding whether healthy Olympians should be given priority in receiving these vaccines could also arise.

During his visit to Japan last month, Bach suggested the news of effective coronavirus vaccines made him "very confident that we can have spectators in the Olympics stadium next year and that spectators will enjoy a safe environment".  

The Olympics is scheduled to take place from July 23 to August 8, followed by the Paralympics from August 24 to September 5.