Switzerland captain Granit Xhaka tested positive for COVID-19 and has been isolated while his team mates went ahead with their friendly against Greece in Basel on Wednesday.
"Xhaka was diagnosed with symptoms on the morning of the game and was immediately isolated in his room. A rapid test turned out negative, the subsequent PCR test, carried out to be on the safe side, produced a positive result in the evening,” said a Swiss Football Association statement.
The Arsenal midfielder, 28, will do another PCR test on Thursday.
The association said local health authorities had ordered no further measures for the team because the other players were all either vaccinated or had previously recovered from the virus but an unidentified staff member had to go into quarantine.