Tokyo Olympics organisers have said they are increasingly concerned about the disruption the fast-spreading virus in China is causing ahead of the Games, which open in just under six months.

Chief executive Toshiro Muto sounded a grave note speaking at a meeting with officials of the International Paralympic Committee.

“I am seriously worried that the spread of the infectious disease could throw cold water on the momentum towards the games,” Mr Muto said. “I hope that it will be stamped out as soon as possible.”

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Saburo Kawabuchi, the mayor of the athletes village where 11,000 Olympians will stay, expressed his apprehension.

“I truly hope that the infectious disease will die down somehow so that we will be able to operate the Paralympics and Olympics smoothly,” he said.

“In the worst case — we will do our utmost for the athletes so that they will be able to concentrate on performing their best.”

Tokyo organisers have repeatedly said there are no plans to cancel the Olympics. That position has been repeated by the Switzerland-based International Olympic Committee (IOC).

But the problems deepen with each passing day. Some Olympic qualifying events have been cancelled, or relocated. Travel restrictions will add more confusion, and travelling fans are likely to be concerned.

Japan has not reported any deaths from the virus. But deaths in mainland China rose to 490 on Wednesday.

“In Japan, we are facing all sorts of problems including coronavirus infections, cyber security and transportation systems,” said Toshiaki Endo, an organising committee vice president.

He added that the IOC “is satisfied with our preparations”.

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Craig Spence, a spokesman for the International Paralympic Committee, tried to be reassuring.

“We have full confidence that the relevant authorities, in particular here in Japan and the World Health Organisation, will take all the necessary measures to address the situation.”

Japanese Prime Minister Shino Abe was asked on Monday about the viral outbreak and the impact on the Olympics. He brushed aside worries.