An explosion ripped through a West Virginia coal mine owned by Massey Energy, killing at least 25 miners in the deadliest US mining disaster since 1984.

Governor Joe Manchin said yesterday morning that four miners remained missing deep underground and that 11 of the dead had been identified. "You can imagine the anxiety for the family members," Manchin told the CBS "Early Show."

The explosion occurred Monday afternoon at the Upper Big Branch Mine in Montcoal, about 48 km south of the state capital Charleston.

The mine, owned by Massey's Performance Coal subsidiary, has two emergency chambers stocked with food, water and enough air to survive for four days, and rescuers were still hoping the missing miners had made their way there.

"This is still a rescue operation," said Kevin Stricklin of the US Mine Safety and Health Administration. "We can't give up hope at all. All we have left is hope."

But about 50 rescuers were forced to pull back from the search area earlier because methane gas and smoke underground made it too hazardous to continue the search.

The high concentration of gases suggests there may have been a second explosion, Mr Stricklin said.