KETCHUM, Okla. (AP) - Authorities say four members of one family have died in a fire at a home in northeastern Oklahoma.

Assistant state Fire Marshal Sam Schaffnitt told reporters that the victims of the early Sunday morning are a 66-year-old woman, her son who was in his 30s, and her 12- and 14-year-old grandchildren. No names were immediately released.

Schaffnitt said the four lived in a mobile home north of Ketchum and that the home was engulfed in flames when firefighters arrived about 1:30 a.m.

Schaffnitt said two investigators are on the scene trying to determine the cause of the fire.