Japan's health ministry says coronavirus infections in the country remain on a gradual upward trend and rose from the previous week in 42 prefectures out of 47.

The health ministry says the weekly report for the 7-day period until May 21 provided by about 5,000 medical institutions identified 17,489 new coronavirus cases. That's up 4,567 cases from a week ago.

The ministry also says the average number of COVID-19 patients per medical institution was 3.56.

The figure is 1.35 times that for the previous week and marks the seventh consecutive week it has increased.

Okinawa Prefecture had the largest number of 10.8 patients, followed by Ishikawa with 6.38, Iwate with 6.32, Niigata with 6.11 and Yamanashi with 5.68.

The ministry also says the number of new hospitalizations in Japan from COVID-19 over the week to Sunday was 3,215, up 726 from the previous week.

Ministry officials say coronavirus infections are at relatively low levels, but they have gradually risen since April and more people have been hospitalized. They say that they will closely monitor the situation.