MONTCOAL, W.Va. (AP) - Massey Energy says 25 workers have been killed in a West Virginia coal mine explosion in the worst U.S. mine disaster since 1984.

An explosion Monday afternoon rocked the remote coal mine with a history of safety problems.

Rescuers had been trying to get to at least 10 miners they thought were trapped.

However, the rescue has been halted even though officials say four men were still unaccounted for early Tuesday.

In 1984, 27 were killed by a fire at Emery Mining Corp.'s mine in Orangeville, Utah.