it was officially known as the epidemic prevention and water purification department of the kwantung army. originally set up by the military police of the empire of japan, unit 731 was taken over and commanded until the end of the war by general shirō ishii, a combat medic officer in the kwantung army. the program received generous support from the japanese government until the end of the war in 1945. unit 731 and other units operated biological weapon production, testing, deployment, and storage facilities. they routinely conducted tests on human beings (who were internally referred to as "logs"). additionally, biological weapons were tested in the field on cities and towns in china.