Explosions in two Chinese coal mines have left at least 53 workers dead and six missing, the official Xinhua News Agency and safety officials said Sunday.

Both blasts occurred the same day and together have incurred the highest reported death toll for one day in China's notoriously dangerous mines in recent weeks.

The first occurred Saturday in the Yuanhua Coal Mine in Jixi, a city in northeast Heilongjiang province, Xinhua said.

By Sunday, the remains of 21 miners had been found, while six miners were still missing, Xinhua said. Four managed to escape.

In the southwestern province of Yunnan, the death toll from a gas explosion in a shaft in Fuyuan county rose overnight from 20 to at least 32 miners as rescuers found more bodies, Xinhua said. Another 28 miners were injured in the blast, it said.

Authorities in Fuyuan reached by phone on Sunday said they had no information about the incident. A woman who answered the telephone at the State Administration of Work Safety confirmed that 32 miner had died and said "the rescue work is continuing." She refused to give her name or any other details.

The cause of both explosions was under investigation, Xinhua said.

China's mines are the world's deadliest, with thousands of workers dying each year in explosions, fires and floods, many caused by inattention to safety regulations and the lack of proper equipment.