A small explosion that occurred Friday afternoon at an underground coal mine in Pennsylvania killed at least nine people and injured about two dozen others, according to the U of P. The explosion occurred about 1:30 p.m. local time, the UofP said in a statement.

    “This is an extremely dangerous time for everyone in the community, including our first responders, who have been deployed to the scene,” U of T Public Safety Chair Robert-Jan Barthelsen said in the statement.

    It was not immediately clear what caused the explosion.

    U. of P President Michael Curry said he was “shocked and saddened” by the loss of life.

    “It’s a devastating event and a devastating tragedy,” Curry said.

    “Our thoughts are with those affected by this terrible tragedy.”

    The Associated Press reported that the blast happened when a water pipe and a water heater were in contact with each other and that water had been leaking into the mine.

    The blast also blew a nearby power transformer, causing it to explode.

    U of PA said the cause of the explosion was not yet known.

    The Associated News contributed to this report.