Local authorities found explosives at the site of a hospital parking lot blast that killed at least 30 people, the government said Tuesday.

The blast occurred Monday in an underground garage at a hospital for employees of the Xuangang Coal and Electricity Co. Ltd. in Yuanping city, Shanxi province.

The blast also injured villagers who were living close by, the official Xinhua News Agency said.

Authorities were investigating "large quantities of detonators and blasting fuses" found at the site, Xinhua said.

The company had "no idea how many people were still missing," Li Jianzhang, an official with Xuangang, was quoted as saying.

The report did not give any more details on where the bodies had been found, and said the death toll might rise as rescue efforts continue.

A two-story residence directly above the garage was destroyed, Li You, a hospital official, said Monday.

Another nearby five-story residence, which houses hospital staff, was badly damaged, he said. Many of the windows were blown out.