Experts from Japan and China began to excavate Japanese chemical weapons abandoned after World War II in Ning'an City, northeast China's Heilongjiang Province on Wednesday.

More than 20 Japanese experts, dispatched by the Japanese government at the request of the Chinese government, have arrived at the site - the yard of Ning'an Chemical and Light Industry Company. Over the course of the next eight days, they will confirm the weapons and dispose of them, assisted by Chinese experts.

After Japan surrendered in 1945, its forces dumped a large quantity of chemical weapons in China.

According to the office dealing with the issue of the abandoned weapons under the Chinese Foreign Ministry, the two sides began preparations for the disposal program on June 30.

Figures from the Foreign Ministry show that Japan abandoned at least 2million tons of chemical weapons in China. A total of 2,000 Chinese people have been killed by the chemical weapons since 1945.

China and Japan joined the United Nations Chemical Weapons Convention in 1997. Two years later, the two sides signed a memorandum, in which Japan admitted that it had abandoned a large amount of chemical weapons in China at the end of World War II. It also agreed to provide all the necessary funds, equipment and personnel for the retrieval and destruction of all the chemical weapons abandoned by Japan in China by 2007. So far 37,499 chemical weapons have been retrieved.

In August 2003, a toxic leak killed one man and injured 43 after five canisters of mustard gas were unearthed at a construction site in Qiqihaer city of Heilongjiang. Japan has agreed to pay 300 million yen (US$2.75 million) in compensation. The accident was the most serious mustard gas poisoning case since the founding of new China in 1949.

With accidents occurring frequently, China urged the Japanese government to speed up the process of the disposal.

Liu Yiren, head of the office, said abandoning chemical weapons was one of the crimes that the Japanese military had committed in China during the World War II.

"This is a major historical issue between China and Japan," he said.

The weapons also pose threats to the security of the Chinese people and local environment, said Liu.