A firefighter fears that as many as 10 of his relatives have died in a blaze at a house in Pennsylvania.

The fire at the single-family home in the town of Nescopeck was reported at around 2.30am on Friday, after what neighbours described as a loud explosion.

Three victims have been found so far, and authorities say roughly seven people remain unaccounted for.

Harold Baker told the Citizens’ Voice newspaper 10 victims from his family are expected to eventually be found – his son, daughter, father-in-law, brother-in-law, sister-in-law, three grandchildren and two other relatives.

He said 14 people were living in the home, with one out delivering newspapers at the time.

The initial call to the emergency services was to a neighbouring property, but Mr Baker realised it was his family’s residence as the fire engine approached.

“When we turned the corner up here on Dewey (Street), I knew right away what house it was just by looking down the street,” he told the Citizens’ Voice.

“I was on the first engine, and when we pulled up, the whole place was fully involved. We tried to get in to them.”

Mr Baker was relieved of his duties due to his relationship to the victims.

Neighbours reported seeing the front porch consumed by flames after hearing the explosion sound.

Some said they also heard a young man screaming in front of the house: “They’re all dead.”

A criminal investigation is under way, police said, with officers interviewing survivors.