BEIJING - Accidents at two Chinese coal mines have killed at least seven workers as the death toll from a gas explosion at a third mine a week ago rose to 23, the official Xinhua news agency said.

In the latest disaster to hit the coal-dependent nation, two miners were killed on Friday after the wagon in which they were travelling broke free from a steel cord in the Xinchun mine in Jilin province in the northeast, Xinhua said.

The news came as the toll from an explosion on Wednesday at the privately owned Xinpo mine in the central province of Hunan rose to five, with at least 12 still unaccounted for, it said. Both the chief and deputy head of that mine had fled the scene.

Meanwhile, hopes had all but faded for 24 workers missing at the mine in the northern province of Shanxi, where Xinhua said 23 miners were now known to have died in a gas blast a week ago.

China, which relies on coal to fuel around 70 percent of its energy consumption, has the world's deadliest mining industry.

Safety regulations are often flouted as production is pushed beyond its limits in the name of profit.

A task force set up by the State Council, or cabinet, on Friday to investigate the cause of the Shanxi accident had criticised poor management and a disregard of safety norms at the mine, Xinhua said.

The mishap was "rooted (in) production safety ignorance and a chaotic management of the mine owner," Xinhua quoted Li Yizhong, chief of China's work safety authority, as saying.

Xinhua said the Xinchun mine in Jilin had flouted recent government orders to halt production until proper safety checks had been carried out.

Accidents in China's coal mines killed 345 miners in October, nearly 50 percent more than in the previous month, despite years of government pledges to improve standards.

Between January and October, around 3,630 Chinese miners died in more than 2,000 accidents.