Fan made the remarks on Thursday during his inspection of the Harbaling site in northeast China's Jilin Province, the largest known disposal site of Japanese abandoned chemical weapons in the country.
"Defying international law, Japanese invaders in China wantonly used chemical weapons on a large scale during their invasion and left behind a large number of them after their defeat," Fan said.
These abandoned chemical weapons still threaten and harm Chinese people's lives and property as well as environmental safety in China, he added.
He urged Japan to carry out its obligations in accordance with the convention on the prohibition of chemical weapons as well as a memo signed between the Chinese and Japanese governments, increase input and accelerate recovery and destruction so as to return clean land to the Chinese people.
Chemical weapons left over by Japanese military forces have been discovered at more than 90 locations in 18 provincial-level regions across China.
At Harbaling alone, it is estimated that around 330,000 such weapons were buried. The cleanup project there is scheduled to be completed in 2022.