Two US military fighter jets are escorting a commercial airliner from the Canadian border to New York City, officials said.
The plane is carrying cargo from Yemen.
The officials said there is no known threat associated with the plane, but it was being escorted to John F Kennedy International Airport as a cautionary move.
It was not clear if the plane had landed yet.
Authorities were tonight investigating whether suspicious packages shipped aboard cargo planes from Yemen to the US were part of a terrorist plot.
FBI spokesman Richard Kolko said the plane – Emirates Airlines Flight 201 which took off from Dubai – was met at JFK by FBI and Port Authority police.
He said the action was being taken solely because the plane was carrying cargo from Yemen.
John Cornelia, a spokesman for US North American Aerospace Defence Command, said the airliner was escorted by a Canadian fighter to the US border, where two US fighters took over.