Illegal storage and production of explosives have led to four blasts in May, killing 16 people and leaving 18 others injured, China's Ministry of Public Security announced on Monday.

All the accidents happened in rural areas, the ministry said, adding that two of them, which killed nine people in Hunan and Hebei provinces were caused by the self-ignition of the explosives illegally kept by coal mine owners and villagers.

Another explosion, which killed four, happened at a villager's home in Henan Province as the village was trying to make a detonator.

The other one, which killed three in Shanxi Province, was still under investigation, the ministry said.

The ministry said that it has asked local authorities to tighten check against illegal possession and production of explosives, especially in the coal-rich areas, to prevent such accidents in the future.

The ministry also asked relevant agencies to improve control over the raw materials that might be used to make explosive, including ammonium nitrate.

China's police have confiscated a total of 12,350 tons of explosives and 502,000 guns in the past five years. The number of explosion and gun violence cases has dropped in recent years, thanks to several national campaigns.

(Xinhua News Agency May 29, 2007)