The Associated Press:

PHILADELPHIA (AP) — Federal authorities are at Philadelphia's airport because of an apparent bomb threat made in connection with an incoming flight from Ireland.

USAirways Flight 777 from Shannon landed at Philadelphia International Airport on Wednesday afternoon.

Law enforcement officials met the plane on the tarmac and passengers exited the jet to waiting buses. FBI spokeswoman Carrie Adamowski says agents are assisting Transportation Security Administration officials in the investigation.

NBC Philadelphia:

Police are not sure at this point what they are dealing with, if anything. They said the threat, which is unsubstantiated, was called in by an unknown male.

This is not an emergency landing. US Air Flight #777 was schedule to land at Philadelphia International today at 2:05 p.m.

According to the airline's website, the flight came in from Shannon, Ireland and arrived at 1:58 p.m.

The flight taxied to a remote area of the airport.