The National Archives of Japan has disclosed the names of 3,607 members of the Imperial Japanese Army's notorious Unit 731, which conducted germ warfare and other biological experiments mainly on prisoners in China before and during World War II, according to a researcher.

Katsuo Nishiyama, professor emeritus of Shiga University of Medical Science and head of the group that requested the disclosure, told The Japan Times on Monday that "it is the first time that almost all of the real names and addresses of the unit's members have been unveiled as a definitive and official document."

The history of secretive Unit 731 had long been concealed. Its commander, Lt. Gen. Shiro Ishii, and others received immunity from prosecution by the International Military Tribunal for the Far East after giving the United States its data on germ warfare.