BEIJING - China's work safety watchdog has vowed to crack down on illegal mining activities and strengthen its efforts to prevent underground flooding, after two recent mine accidents killed 13 people and left three others missing.

The two accidents exposed weaknesses in local mining safety supervision mechanisms and were largely caused by illegal mining and production breaches, the State Administration of Work Safety said in a statement posted on its website.

A coal mine in the city of Qitaihe in Northeast China's Heilongjiang province flooded on August 23 after miners mistakenly drilled into an adjacent flooded mine.

Twenty-two miners have been rescued from the mine alive, but the accident left three miners dead and one still missing.

On August 29, a coal mine in the city of Dazhou in Southwest China's Sichuan province flooded, leaving 10 people dead and 2 missing.

The administration ordered local authorities to step up monitoring efforts for mining activities and eliminate risks to avoid fatal accidents, the statement said.