An explosion at an illegal iron mine killed 24 people in China's northern Hebei province, the official Xinhua News Agency reported Tuesday.

The blast, which also injured five people, took place midday Sunday at an iron mine that was disguised as a wild boar farm in Wu'an city, Xinhua said. The local government did not receive reports of the accident until a day later, Xinhua said.

More than 30 people were initially trapped by the explosion, Xinhua said. The injured were in stable condition at a hospital, Xinhua said.

China's mining industry is the most dangerous in the world, averaging 13 deaths a day from fires, explosions and floods. Many of the accidents are blamed on mine owners who disregard safety rules and fail to invest in required ventilation, fire control and other equipment.