The latest NIID report said nearly 3,000 pediatric clinics across the country recorded an average of 6.31 patients per medical institution during the week to June 23.

Marking an increase for the 13th consecutive week, the figure exceeded the alert-level threshold of five patients per medical institution, which had not been exceeded since August 2019, Xinhua news agency reported.

Regionally, the central Japanese prefecture of Mie reported the highest number of cases with an average of 16.36 patients per clinic, followed by Hyogo Prefecture with 11.12 patients.

HFMD, a viral infection that causes a blister-like rash on the hands, feet, and inside the mouth, mainly affects children under four years of age.

Symptoms include fever, loss of appetite, feeling unwell, skin rashes and sore throat. Mouth ulcers and sores on the tongue, gums, and inside of the cheeks may also indicate HFMD infection.

Children are more at risk of contracting this disease, which can lead to serious complications like encephalitis or dehydration.

Given that HFMD peaks in the summer, Japan's Health Ministry is urging the public to wash hands thoroughly to prevent the spread of the disease.