A former medical officer in Japan's World War II navy admitted to conducting vivisection in the Philippines on some 30 prisoners of war, including women and children, a news report said.
It was the first time such testimony had been given on experiments on human beings by a Japanese officer in the Philippines during World War II, Kyodo News reported late on Saturday.
Similar experiments were conducted in northern China by the notorious germ warfare Unit 731, which is blamed for the deaths of up to 10,000 Chinese and Allied prisoners of war, the report added.
Akira Makino, 84, a former officer of the medical corps of the Imperial Japanese Navy's No. 33 patrol unit, said the experiments on live prisoners began in December 1944, shortly after he was assigned to Zamboanga air base on the Philippines' Mindanao Island.
Makino was ordered to take two local men captured as US spies to a school which had been turned into a hospital, where they were undressed and tied to an operating table, Kyodo said.
Makino was told by his superior to insert a surgical knife into their bodies after the prisoners' faces were covered with an ether-soaked cloth to induce unconsciousness.
"I thought `What a horrible thing I'm doing to innocent people even though I'm ordered to do it,'" Makino said after keeping the information secret for six decades.
The experiments, which included amputating arms and legs, suturing blood vessels and abdominal dissections, continued until February 1945 and resulted in the deaths of some 30 people, including women and children, he said.