Kawashima Kiyoshi, a major general and former chief of the production division in Japan's Unit 731, admitted in his testimony that in central China, Unit 731's expeditionary force collaborated with Unit 1644, a Nanjing-based satellite unit of Unit 731, to carry out military sabotage missions ordered by the headquarters.

"They used plague, cholera and typhoid bacteria to infect Chinese military sites and transportation lines. Civilians in these areas were also forced into the bacteriological warfare," the testimony said.

Kiyoshi acknowledged that the special cultivation of bacteria by Unit 731 and the Japanese military's use of deadly pathogens against Chinese troops and civilians clearly violated international treaties and obligations prohibiting the use of such weapons in warfare.

"I now realized that the methods we used, which involved experimenting on living humans and causing their deaths by infecting them with deadly bacteria, were cruel, inhumane, and criminal acts against humanity," he confessed in one statement.