Two athletes living in the Olympic Village have tested positive for Covid-19.
Organisers confirmed the positive tests on Sunday and both were listed as non-Japanese, but no names or other details were provided.
A third athlete has tested positive but is not living in the Olympic Village, they added.
Organisers said 55 people linked to the Olympics have reported positive tests since July 1.
This accounting includes athletes or others who may have arrived for training camps but are not yet under the “jurisdiction” of the organising committee.
The International Olympic Committee confirmed the test and identified him as Ryu Seung-min of South Korea. He won an Olympic gold medal in table tennis in the 2004 Olympics.
He was reportedly being held in isolation. Reports said he was asymptomatic.
The Olympic Village on Tokyo Bay will house 11,000 Olympic athletes and thousands of other support staff.
Tokyo recorded 1,410 new Covid-19 cases on Saturday, the highest in six months.
It was the 28th straight day that cases were higher than seven days previous.
The Olympics will open on Friday under a state of emergency in Tokyo and three neighbouring prefectures. The emergency order lasts until August 22.