People walk in Tokyo's Kabukicho nightlife district on June 24, 2020. (Kyodo)

TOKYO - The daily number of new coronavirus cases reported in Japan on Friday topped 100 for the first time since May 9, adding to signs that the epidemic is gaining strength since the country eased business and social restrictions.

Of the 105 cases, Tokyo reported 54 -- 31 of them connected to the nightlife industry, such as at so-called host clubs, where women pay to drink with and be entertained by young men. The daily figure for the capital came to around 50 for the third day in a row.

Since Japan lifted a nationwide state of emergency entirely on May 25, it recorded more than 70 new COVID-19 cases for six days and the cumulative number reported each week has been increasing gradually. It was 291 two weeks ago, 407 last week, and has reached more than 500 this week.

While Tokyo has seen the highest number, more than half of the total during the most recent week, Gov. Yuriko Koike on Friday denied that the uptick is a second wave of infection, citing views of public health experts.

The Tokyo governor said a new coronavirus warning system, replacing the current "Tokyo alert," is expected to be introduced as early as by the end of this month.

Under the existing system, Tokyo has to issue the alert under certain conditions such as if the daily average number of new cases exceeds 20 in a week and the ratio for unknown infection routes climbs to more than 50 percent.

About half of those infected in nightlife districts in Tokyo on Friday were from Shinjuku Ward, which hosts Kabukicho, famous for various types of nightclubs.

The metropolitan government said 40 of the infected were in their 20s and 30s.

"The infection is limited to younger people and there is a smaller chance of it getting severe. It hasn't spread widely in the city like in early April, when many from various generations were infected," a Tokyo official said.

The metropolitan government a week ago lifted its advisories against visiting places such as live music venues and nightclubs.

Cases reported Friday by Ibaraki and Kanagawa prefectures near Tokyo, as well as Hyogo Prefecture in western Japan, included commuters to the capital or someone who had been in close contact with an infected person from Tokyo.

Hokkaido in northern Japan has also been reporting at least one new infection a day since April 7.

There have been more than 18,970 infections reported in Japan so far, including 712 from the Diamond Princess cruise ship that was quarantined in Yokohama near Tokyo in February. The country's death toll from the virus stood at 984, with none reported Friday.