HARBIN: Residents of Qiqihar, the second largest city in Northeast China's Heilongjiang Province, have long learned to be wary of weapons left by Japanese wartime aggressors.

However, the latest discovery last Wednesday of 28 bombs along the banks of the Nenjiang River has left authorities weary.

The shells are just ordinary ones, not chemical ones that killed one person and injured another 43 in August 2003 in a construction site in the city.

However, they can still be deadly as most of them have not been defused and may explode if there is a strong shock or vibration.

"We often hear or see reports that a man accidentally ignited a bomb left by the Japanese and got hurt or crippled," said Yao Shu from the Qiqihar Public Security Bureau.

"Now, every resident knows to dial 110 to call the police when they encounter a shell," Yao said, "But no one knows how many of them there are and where they are hidden."

Yao said that few people knew that Qiqihar was also an experimental base for Unit 516, a Japanese unit that experimented with chemical weapons.

Gao Xiaoyan, a researcher with Heilongjiang Provincial Academy of Social Sciences, said that Unit 516 is less well known than the notorious Unit 731 in provincial capital Harbin due to a lack of research materials.

"Unlike Unit 731, which developed biological weapons, Unit 516 mainly produced chemical weapons." Gao said.

Japanese troops destroyed all the materials and dumped the unused weapons in wells and rivers before they fled after their surrender in 1945, Gao said.

"However, little was known about the exact amount of chemical weapons left by them due to a lack of materials," Gao said.

Japan has promised to send expert teams to destroy chemical weapons left in China.

Earlier this month, a joint-team formed by experts from both countries retrieved a total of 689 shells and bombs, of which 210 were confirmed to be chemical weapons, in Heilongjiang's Ning'an.

So far 37,499 chemical weapons and 200 tons of contaminated items have been collected but none have been destroyed, Xinhua News Agency reported.

"We are rather dissatisfied with Japan's slow pace of disposal," said Liu Yiren, director of the Office of Japanese Abandoned Chemical Weapons in China affiliated to the Ministry of Foreign Affairs.

Source: China Daily