Workers in the city of Harbin, Heilongjiang province have found more than 1,000 items, over the past two years, at the nearby site of Japan’s biological-warfare team, Unit 731, during WWII, according to a press conference held by the provincial culture department in Harbin, on July 23.

New findings of cultural relics researchers and archaeologists at the site include glass vessels and ceramics, in a 15,000-square-meter area that contained a bacteria lab, prison, and bacteria bomb plant.

The findings also involve incineration pits and traces of explosives that the Japanese attempted to destroy to cover up their crimes before retreat.

Li Chenqi, a researcher with the provincial Cultural Relic and Archaeology Institute, says they will expand the excavation work to try to find more evidences of the Japanese experiments by 2021.

The notorious Unit 731 was a top-secret biological and chemical warfare research facility established in 1935 and a nerve center for Japan's biological warfare campaign in China and SE Asia during WWII. The retreating Japanese blew up the base when the Soviet Union took Harbin in 1945.