Firefighters from three municipalities responded to the blaze, which was reported as having "fully engulfed" the residence when officials arrived shortly before 9:30 p.m. EDT, the Elmira Star-Gazette reported.
Firefighters began a search-and-rescue operation after being told people were inside. The victims were found on the second floor.
While Elmira police had not named the victims, numerous postings on Facebook identified one of the dead as Courtney Stanton. The newspaper said her profile indicated she was 17 years old and a student at Southside High School.
A message written in chalk in front of the home said, "R.I.P Nidal, Amera, Jordan, Courtny We love you. We love you guys so much," the newspaper said
A neighbor had said earlier four children, ages 5 to 15, lived in the home.
The blaze was being investigated by city police and fire officials, along with the state Office of Fire Prevention and Control.
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