BEIJING (AFP) - 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 around 6pm on Saturday (Dec 15) after the connecting segment of a mining skip broke, causing it to plummet down the mine shaft, the official Xinhua news agency said.

The three injured miners were rushed to hospital following the accident, which took place in south-western 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.

According to China's National Coal Mine Safety Administration, the country saw 375 coal mining related deaths in 2017, down 28.7 per cent year on year.

However, 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.