Police in north China's Shanxi Province have arrested four men in connection with an explosion that killed 34 people in a hospital compound last month.

Rescuers dig through debris yesterday after an explosion severely damaged a five-storey dormitory housing medical staff at Xuangang Coal and Electricity Co. Ltd. in Yuanping, North China's Shanxi Province. [Newsphoto]

The People's Procuratorate in Yuanping City instructed police to make the arrests on Wednesday.

The four, allegedly led by 41-year-old Wang Jinsheng, are accused of illegally trading, transporting and storing more than three tons of explosives that caused the blast, a source with the procuratorate said on Friday.

Wang, a former private mine operator and administrator of the staff hospital affiliated to the Xuangang Coal and Electricity Company, placed 3,744 kilograms of explosives and 10,000 detonators in the hospital garage on March 28. He had bought the explosives for his private colliery.

But the explosives detonated early on April 10, destroying the two-story garage and damaging houses and buildings within a one-kilometer radius.

Most of the victims were hospital staff and their families, when the explosion wrecked one end of a five-story residential building for hospital workers.

Three others have been arrested for helping Wang buy and store the explosives, including Wang's colleague Liu Yueqing, his chauffeur, 31-year-old Wang Guohua and his colliery storeman Jia Sanwa.

The police are also searching for Qi Er, who is alleged to have made explosives illegally.