The FBI is looking at terrorism as a possible motive in the stabbing of an officer at the Flint, Michigan, airport.
A law enforcement official said the investigation of the Wednesday morning assault at Bishop International Airport is in its early stages.
A second law enforcement official said authorities were investigating witness claims of what the suspect said during the incident, including possibly "Allah akbar", the Arabic phrase for "God is great".
Michigan State Police Lt Mike Shaw says one person is in custody and nobody else is believed to have been involved.
Lt Shaw identified the officer who was stabbed is Lt Jeff Neville with the Bishop International Airport police.
He says Lt Neville's condition also has been upgraded from critical to stable condition.