A predawn house fire Thursday that killed two men in the city’s Nicetown section has been ruled an arson and is being investigated as a homicide case, police said.

Firefighters and police responded to the blaze just before 4 a.m. on the 1400 block of West Jerome Street. Two men in their 50s were found in an upstairs bedroom and were transported to Temple University Hospital and Einstein Medical Center. Both were pronounced dead shortly before 5 a.m. Their names were not released.

Investigators from the Philadelphia Fire Department and the ATF Arson Task Force found an accelerant was used inside the front door.

Police said the motive for the arson was unknown.