GANADO, Ariz. — Authorities say an infant's remains have been found on the Navajo Nation in Arizona.

The Gallup (New Mexico) Independent reportsthat Navajo Police Chief Phillip Francisco said a child's severed head was found Monday in field near Ganado.

Francisco told the newspaper the FBI is investigating and he didn't have additional details.

Francisco's office says he's unavailable for comment Thursday because of the funeral of a Navajo Nation police officer killed on duty.

The FBI told The Associated Press in a brief statement Thursday that "partial remains of an infant child" were found in the Ganado area.

FBI spokeswoman Jill McCabe said no additional information is available.

The FBI previously told the Independent that authorities had information they hoped would lead to "a rapid resolution to the investigation."