The International Cycling Union (UCI) said that two Tour de France riders have not returned negative COVID-19 results from tests conducted on Sunday.
The two riders, who "do not rank within the top 20 of the general classification", will neeed "complementary biological examination", the UCI said in a statement.
"While these riders are completely asymptomatic, security measures (isolation of the two riders) have been implemented to protect the other participants.
"A final decision on their participation will be taken by tomorrow (Tuesday) morning in a collegial manner by the concerned parties (COVID-19 event and team doctors, and the UCI medical director."
The UCI did not clearly say whether those two riders had tested positive and the body was unable to be reached by Reuters for clarification.
Eight riders have so far pulled out of the race after being infected with the novel coronavirus and showing symptoms as part of the teams' international testing protocol.
Last year, if two members of a team tested positive for COVID the whole outfit would be sent packing, which is not the case in this edition.
Whether a rider who tests positive can stay in the race is decided following a meeting between race, UCI and team doctors, depending on the rider's viral load.
