Photo/Illutration The Okinawa prefectural government building in Naha (Asahi Shimbun file photo)

NAHA--A novel coronavirus cluster infection has killed 64 inpatients and spread to 135 others at a hospital in Uruma, Okinawa Prefecture, according to the prefecture and the hospital.

The death toll at Uruma Kinen hospital began rising after the medical institution on July 19 confirmed that inpatients and staff members had contracted the virus, according to the hospital.

As of Aug. 17, 199 people--26 staff members and 173 inpatients--had tested positive.

Many of the 64 deaths were elderly patients. Some died after being transferred to other hospitals, the hospital said.

The prefecture is investigating what caused the rapid spread of the virus at the hospital.