The Tokyo metropolitan government said Monday it has confirmed an additional 48 coronavirus infections in the capital, the biggest daily increase since early May.

The number topped the previous day's 47 and included many who work at nightclubs and other similar entertainment establishments, fueling concerns Japan could face a rebound of virus cases after it lifted a state of emergency and allowed business to restart.

A total of 5,592 infections have been confirmed in Tokyo, the worst among the nation's 47 prefectures.

The latest figure is the highest since May 5 when the Tokyo government reported 57 cases.

About 20 of the 48 were confirmed through group testing on people working at nightlife establishments, a new measure introduced in Tokyo, the metropolitan government said.

New infections in Tokyo had been on a declining trend through late May. But they rebounded after the state of emergency was lifted on May 25 for the last batch of prefectures including Tokyo.

While 29 prefectures have reported zero new infections in the three weeks since the state of emergency was fully lifted, the outbreak shows no signs of slowing in Tokyo and Hokkaido.

The number of new infections has been increasing in Tokyo every week, with those under 40 making up over 60 percent of the cases.

On June 2 when the daily increase reached 34, the metropolitan government issued a warning called "Tokyo alert" to raise public awareness.

It removed the warning last Thursday and further relaxed restrictions on business activities in the capital at midnight Thursday, allowing karaoke boxes, arcade centers and pachinko parlors to reopen, as well as restaurants and pubs to operate longer hours.

In Hokkaido, where over 30 new cases have been confirmed every week, cluster infections have occurred among older people patronizing karaoke cafes. More than 20 workers and customers were infected at two cafes in Sapporo, with those over 60 making up half of them.

In contrast, Osaka Prefecture, which has the second-highest total number of coronavirus cases, has managed to keep new daily cases to almost zero since May 25.

The central government is considering permitting travel between the Tokyo metropolitan area, Hokkaido and other regions, as well as relaxing immigration restrictions from Friday, provided infection numbers per 100,000 people and other benchmarks are met.

Around 20 people have tested positive for the virus every week upon arrival at airports, but the majority show no symptoms, according to health authorities.

Japan is considering gradually easing the entry bans currently imposed on 111 countries and regions. But health experts say the government at the same time has to ensure it is taking thorough quarantine measures to prevent the spread of infections.

The burden on the health care system has also been lessened. While over 1,800 patients were hospitalized in Tokyo in late April, there were only 271 as of last Wednesday, according to data from the health ministry. The numbers of hospitalizations and serious cases have been on a downtrend in almost all prefectures.

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