An athlete from Lithuania who arrived in Japan this week to compete at the Tokyo Olympics is suspected of having COVID-19, the city of Hiratsuka that is hosting the delegation's pre-games camp said Friday.

The male swimmer in his 30s tested negative upon arrival at Tokyo's Haneda airport on Wednesday, but a polymerase chain reaction test he took the following day at his hotel after traveling to Hiratsuka near the capital came back positive, according to the city.

However, a test he took at a medical institution on Friday afternoon came back negative. The athlete will undergo another test on Saturday to determine whether he is infected with the virus.

With two weeks remaining until the opening of the Olympics, athletes and officials from many countries have been arriving en masse to take part in training camps. However, the border controls in place for them have come under public scrutiny amid persistent concern that the games could lead to a further surge in infections.

The Lithuanian swimmer had trained in a pool before his test result came back positive on Friday morning. The members of the delegation only traveled between their training facility and their hotel using a designated vehicle, according to the city.

Health authorities are determining who may have come into close contact with the swimmer, the city said.

Hiratsuka is set to host a total of 63 athletes, coaches and officials from Lithuania until Aug. 5.

In a related development, a member of the Israeli delegation tested positive for COVID-19 after arriving in Japan on Friday and is quarantining at a designated facility, a source familiar with the matter said.