China's official news agency says 21 miners were trapped underground early Saturday when a coal mine in southwestern Guizhou Province flooded.

The Xinhua news agency said 29 miners were working in two shafts of the Niupeng Mine in Pingtang County when the mine was flooded. Eight of the miners have been rescued.

China's coal mines are the world's deadliest, with thousands of miners dying every year. China's massive demand for coal induces many producers to ignore and cut corners on safety regulations.