A woman infected in Japan's first case of the lambda coronavirus variant has been identified as a person associated with the recently ended Tokyo Olympics, government sources said Friday.

The woman in her 30s had traveled to Peru where the variant, feared to be more contagious and more resistant to vaccines, was first detected. She arrived at Haneda Airport in Tokyo on July 20 with her Olympic accreditation card, according to the sources.

The National Institute of Infectious Diseases confirmed her infection with the variant after she was found positive in a test conducted at the airport.

The sources said the woman had developed no symptoms and is likely to have been moved to quarantine accommodation.

The organizing committee of the Olympics and Paralympics released the number of COVID-19 cases associated with the Summer Games on a daily basis without disclosing infected individuals' nationality or the coronavirus variant they were infected with. Coronavirus cases related to the Olympics totaled 553.

The World Health Organization has designated the lambda strain as a "variant of interest," a degree lower than delta, labeled a "variant of concern." The lambda variant has not been designated as of interest or concern in Japan.

Takaji Wakita, the head of the national institute who chairs the health ministry's pandemic response panel, told a news conference earlier this week that designating the lambda strain as a variant of interest will be considered if cases involving it increase.

Some researchers say the lambda variant is more resistant to vaccines than the original version of the virus.