Seven miners were killed and three others injured in an accident at a coal mine in south-western China, state media reported.

The accident occurred at around 6pm local time on Saturday after the connecting segment of a mining skip broke, causing it to plummet down the mine shaft, the official Xinhua news agency said.

Three injured miners were rushed to hospital following the accident, which took place in Chongqing municipality.

The cause of the incident is still under investigation.

Deadly mining accidents are common in China, where the industry has a poor safety record, despite efforts to improve coal production conditions and crack down on illegal mines.

In October, 21 miners died in eastern Shandong province after pressure inside a mine caused rocks to fracture and break, blocking the tunnel and trapping the workers. Only one miner was rescued alive.

In December 2016, explosions in two separate coal mines in the Inner Mongolia region and in north-eastern Heilongjiang province killed at least 59 people.

China is the world’s largest producer of coal. According to the country’s national coal mine safety administration, the China saw 375 coal mining-related deaths in 2017, down 28.7% year-on-year.

But despite improvements, “the situation of coal mine safety production is still grim,” said the bureau in a statement following a coal mine safety conference in January.

