A kidney donor has died during a transplant operation for the first time in Japan, the Japan Society for Transplantation said Thursday.

The 65-year-old woman suffered massive bleeding and died during endoscopic surgery to remove a kidney for transplantation into her son at Doujin Hospital in Urasoe, Okinawa Prefecture, last Saturday, the hospital said.

The son, 43, received the kidney, the society said.

The hospital reported the matter to police and to the transplant society and created a panel to look into what happened. The causes of the bleeding and death are unknown.

On Wednesday, the society asked the hospital to set up a third-party investigative panel and announce the incident without delay.

It plans to send experts to check if there were problems with the surgery.