101608macarthurairport.JPGPart of the Southwest Airlines terminal at MacArthur Airport on Long Island was evacuated for about an hour this morning after an improvised explosive device was found in the carry-on bag of an unidentified man. Officials say they won't be able to determine what the device is until it's defused and examined, but it's believed to be either a smoke bomb, pipe bomb or firework. It was spotted by TSA baggage screeners as the 20-year-old attempted to board a flight to Las Vegas, where he resides. The TSA then pulled his checked luggage and found a knife and fireworks, including M-80s. The FBI and agents from the DOJ's Joint Terrorism Task Force are on the scene; FBI spokeswoman Lara Uselding tells Newsday the man has "no known nexus to terrorism." At least four outgoing flights were delayed following the incident.