PITTSBURGH—A western Pennsylvania medical examiner says the two children who died in a house fire last week were killed by "acute smoke inhalation."

The Allegheny County medical examiner's office ruled the deaths of 3-year-old Irihanna Hayward and 4-year-old Kamari Thomas accidental.

Authorities said the blaze began at about 3:20 p.m. Friday in the Greenfield neighborhood of Pittsburgh.

The children's baby sitter was hospitalized after jumping from a third-floor window of the row house to escape the flames.

Authorities say the cause of the fire remains under investigation.