Four competitors including a shooting world number one saw their Tokyo Olympic dreams dashed after testing positive for the coronavirus.

British shooter Amber Hill, top-ranked in the women's skeet, was forced to pull out before she departed for Japan after testing positive. The other athletes included table tennis player Pavel Sirucek, Chilean taekwondo competitor Fernanda Aguirre and Dutch skateboarder Candy Jacobs, AFP reported.

The Tokyo Olympics are being staged in biosecure “bubble” conditions, with athletes tested daily and under orders to stay socially distanced and wear masks when not competing, training, eating or sleeping.

But the latest cases show that competitors are treading a fine line.