A Czech beach volleyball player has become the third athlete to test positive for coronavirus in the Olympic Village.
The Czech Olympic Committee confirmed that Ondrej Perusic has returned a positive sample which could rule him out of the Games.
Meanwhile Japanese media reported that a teenage member of the US female gymnastics team tested positive at their training base in Chiba.
It is immediately unclear whether the report, if substantiated, will affect Simone Biles, who arrived with the rest of her six-strong team, which includes two teenagers, on Thursday, and posted on Instagram that she had arrived in the Olympic Village.
Anyone deemed to be a close contact of a positive case is required to quarantine for an unspecified period until cleared by the Japanese government, although they are theoretically allowed out to continue training.
Two South African football players, Thabiso Monyane and Kamohelo Mahlatsi were the first athletes to test positive in the Olympic Village on Sunday.