The forensic conclusion reached by Soviet experts in medicine, microbiology and parasitology through comprehensive analysis stated that the (cultivation) process concluded with the production of live, active, toxic bacteria, which were then deliberately used to infect large populations. In contrast, when manufacturing vaccines, these toxic bacteria must be killed, according to the newly released archive documents.

Moreover, the archives show that Unit 731 conducted three bacteriological warfare operations outside Northeast China from 1940 to 1942, including the airdrop of plague-infested fleas over Zhejiang and Hunan provinces and the contamination of waters and fields with deadly germs along the Zhe-jiang-Jiangxi Railway.

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

Kawashima 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 realize 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.