In this photo released by China's Xinhua News Agency, a worker is carried on a stretcher out of the Longyun coal mine in Yuncheng County, east China's Shandong Province, Sunday, Oct. 21, 2018. Twenty were trapped in the coal mine Sunday after a rock burst destroyed part of a mining tunnel. (Guo Xulei/Xinhua via AP)

In this photo released by China's Xinhua News Agency, a worker is carried on a stretcher out of the Longyun coal mine in Yuncheng County, east China's Shandong Province, Sunday, Oct. 21, 2018. Twenty were trapped in the coal mine Sunday after a rock burst destroyed part of a mining tunnel. (Guo Xulei/Xinhua via AP)

BEIJING (AP) — Two people died and 18 were trapped in a coal mine in eastern China on Sunday after a rock burst destroyed part of a mining tunnel, state broadcaster China Central Television reported.

The spontaneous fracturing of rock — a kind of earthquake induced by excavation — took place around 11 p.m. Saturday in Shandong province. Part of a water drainage tunnel was destroyed in the burst, said the official Xinhua News Agency, and two people were killed by fractured rocks that fell in the tunnel.

More than 300 people were working inside the mine at the time of the rock burst, and most were successfully lifted to safety.

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Eighteen remained trapped underground late Sunday. Two people who were trapped have been rescued, according to China Central Television.

The incident “has nothing to do with workers’ operations,” an official with the Shandong Coal Mine Safety Supervision Bureau told The Associated Press by phone. The official, surnamed Tian, said nearly 140 rescuers were dispatched.

Ventilation has returned to around 200 meters (656 feet) of the damaged tunnel, Xinhua said.

The cause of the accident was being investigated.