Tokyo, Jul 20 (IANS): A day after it emerged that a US reserve gymnast had tested COVID-19 positive at a training centre near Tokyo, the father of the 18-year-old female athlete said that his daughter was "asymptomatic and had been fully vaccinated" for the disease.

Kara Eaker, an Olympic reserve on the US women's gymnastics team, had tested positive for COVID-19 on Monday.

Eaker's father Mark told the media on late on Monday that his daughter had tested positive at the team's training camp in Inzai, 30 kilometres east of Tokyo.

"We confirmed today that a teen athlete of the team has tested positive," said Kimiya Kosaku, an Inzai city official, adding that she had arrived in Japan on July 15.

"Another athlete has been categorised as a close contact and is also staying alone inside her room," Kosaku said.

Eaker's personal coach Al Fong also confirmed the positive test on Monday.

The result came after Eaker received what was described as a "false positive" over the weekend. Eaker took a subsequent test that was negative before testing positive again multiple times.

Four alternates, including Eaker, travelled to Japan with the six-woman US Olympic gymnastics team of world and Olympic champion Simone Biles, Jordan Chiles, Grace McCallum, Sunisa Lee, MyKayla Skinner and Jade Carey.

The alternates have been rooming with other alternates since arriving in Japan, with the competitive team rooming with fellow competitors.