A Nigerian delegate to the Olympics became the first visitor to the Tokyo Games admitted to hospital with Covid-19, broadcaster TV Asahi said on Friday.
This has come as Japan battles to stem rising local infections a week before the event.
The individual, a non-athlete in his 60s, tested positive on Thursday evening at the airport with mild symptoms but was hospitalised because of age and pre-existing conditions, the broadcaster said.
The TV station did not give further details however.
On Friday, the Australian Olympic Committee said that tennis player Alex de Minaur, ranked 15th in the world, had tested positive prior to his departure for the Games.
He thus became the latest athlete to have the virus shatter his Olympics dream.