BEIJING (AP) — State media are reporting that an explosion at a Chinese colliery Friday has left 43 miners trapped below ground.

Explosives went off accidentally deep in the pit of the mine located on the outskirts of the city of Xiaoyi in the northern province of Shanxi, the official Xinhua News Agency reported.

It said 15 workers escaped the blast at the mine, operated by the Anxin Coal Mining Corp., which happened shortly after 1:00 p.m.

A state television report that aired four hours later said the condition of those trapped below was still unknown.