Mr. Luis A. Diaz, US Department of Transportation, Federal Aviation Administration, gives instructions to a US Army (USA) Reserve soldier assigned to the 125th Military Police Battalion, Puerto Rico National Guard on the metal detector at the Luis Munoz Marin International Airport at San Juan, Puerto Rico. Members of the National Guard were mobilized in response to request for higher security at airports across the nation in the aftermath of the September 11th terrorist attack on the World Trade Center and the Pentagon