The Japanese government plans to extend the COVID-19 state of emergency set to expire at the end of May in Tokyo and eight prefectures to June 20, a senior official said Thursday, as the decline in infections has slowed and hospitals remain under strain.

Prime Minister Yoshihide Suga said the government will consult with an expert panel on Friday regarding the decision, which will also apply to Hokkaido, Aichi, Kyoto, Osaka, Hyogo, Okayama, Hiroshima and Fukuoka.

The expected extension comes with less than two months until the Tokyo Olympics kick off, casting further doubt over whether the games can be held safely during a global pandemic.

Infections are declining in some areas including Tokyo and Osaka but "on the whole the situation is highly unpredictable," Suga told reporters after meeting with members of his Cabinet including health minister Norihisa Tamura and Yasutoshi Nishimura, the minister in charge of the coronavirus response.

Tokyo Gov. Yuriko Koike and other prefectural leaders have called on the government to enable them to maintain tougher restrictions beyond the current deadline of May 31, including a ban on restaurants serving alcohol and telling them to close by 8 p.m. as well as a cap on attendance at sports games and concerts.

Okinawa, the 10th and most recent addition to areas under the state of emergency, is already set to remain under the state of emergency until June 20.

Another 4,140 coronavirus cases were reported across Japan on Thursday, down from more than 7,200 at the peak of the country's fourth wave of infections. There were 1,371 COVID-19 patients in serious condition, 42 fewer than the previous day, according to the Ministry of Health, Labor and Welfare.

But hospitals in some areas are still struggling to secure enough beds and there is growing concern about a faster-spreading India variant of the virus.

The government is also set to extend the quasi-emergency set to end on May 31 in five prefectures -- Saitama, Chiba, Kanagawa, Gifu and Mie -- until June 20, the senior official said on condition of anonymity.

The June 13 deadline for the measure, which entails similar restrictions to the state of emergency but with smaller penalties, in Gunma, Ishikawa and Kumamoto is set to remain intact.