WASHINGTON, Jan. 2 (Xinhuanet) -- Thirteen coal miners were trapped underground after a coal mine explosion in West Virginia on Monday morning, local media reported.

    The miners were trapped more than one mile (about 1.6 km) underground in the mine in Upshur County.

    Six miners managed to escape the explosion while the condition of the 13 trapped was not immediately known.

    Four coworkers tried to reach the trapped miners, but their effort was unsuccessful, the report said.

    A special mine rescue team has been sent to the scene to rescue the miners.

    The cause of the explosion was still unknown. Enditem