Six miners died and six others remain trapped underground after a coal mine flooded in southwest China's Sichuan Province, local authorities said Tuesday.

The flood occurred around 10 a.m. Monday, when 30 miners were working underground in the Zengjiagou Coal Mine in the city of Dazhou. Eighteen of the miners managed to escape, according to a spokesman from the provincial work safety bureau.

Rescuers have retrieved six bodies and are working to reach the remaining miners, the spokesman said.

The manager of the coal mine in under police custody, he said.

Local authorities are investigating the cause of the accident, he added.

In a related incident, 19 miners were pulled alive from a flooded pit in northeast China's Heilongjiang Province Tuesday after being trapped underground for a week, bringing the total number of rescued miners to 22.

Rescuers are still searching for three miners who remain trapped in the mine.