AP PHOTO Firefighters look on after containing a fire at a home on Washington Avenue in Mason City on Wednesday. The cause of the fire is under investigation. The fire killed four children and injured two other people.

MASON CITY — A house fire that killed four children in northern Iowa was caused by an electrical power strip, authorities said Thursday.

The blaze was reported early Wednesday in Mason City, and when firefighters arrived they found flames engulfing the first and second stories of the home, built in the 1880s.

Fire officials said the blaze began at a power strip on the main floor of the three-story home, according to KIMT-TV, though they did not specify how the strip caused it.

The four children killed were identified as John Michael Mcluer, 12; Odin Thor Mcluer, 10; Drako Mcluer, 6; and Phenix Mcluer, 3.

Two residents — John Michael Mcluer, 55, and Ravan Dawn Mcluer, 11 — escaped. They suffered burns and were treated at a hospital.