Tokyo has discovered its first case of community transmission of the omicron variant of the coronavirus, Tokyo Gov. Yuriko Koike said Friday, a sign that it is slowly but steadily spreading in the nation.

The announcement comes after cases of omicron community transmission were detected in Osaka and Kyoto prefectures earlier this week.

"One of the omicron cases reported has no recent history of traveling abroad and it is unclear where it was transmitted from," Koike said in a news conference. "So it's a case of community transmission."

The patient — a doctor who works at a clinic in Tokyo — is currently hospitalized. The gender of the patient was not revealed.

Five people, including family members, have been judged to be close contacts. All of them are asymptomatic and have so far tested negative for COVID-19.

Koike said those who have been treated at the clinic were not designated as close contacts, as the doctor has worn face guards.

Three other people in Tokyo who returned from abroad were confirmed to have been infected with the variant, Koike said.

Following the first confirmed case of community transmission, the metropolitan government will offer free COVID-19 testing starting Saturday, she said. The authorities will make a total of 30,000 such tests available per day at 180 locations by the end of next week.

Separately on Friday, Kyoto Gov. Takatoshi Nishiwaki announced that three cases of community transmission of the omicron variant were confirmed in Kyoto, bringing the total number of such cases in the prefecture to four. Kyoto reported its first case of community infection with omicron on Thursday, but the latest cases were not close contacts of that case, Nishiwaki said.

"Considering that more people will be in contact with each other in the year-end and New Year's holidays, we need to deal with it with a sense of crisis," Nishiwaki told a news conference.