(CNN) -- Six people, including four children, were killed in a house fire late Sunday night in Pottsville, Pennsylvania, Schuylkill Haven borough police said.
Investigators aren't sure of the ages or relations between the deceased.
The Pottsville fire marshal and coroner's office are investing. The cause of the fire is unknown.
CNN's Jake Carpenter contributed to this report.
™ & © 2013 Cable News Network, Inc., a Time Warner Company. All rights reserved.