Fighter jets track military blimp drifting over Pa.

WASHINGTON (AP) — The Pentagon says U.S. fighter jets are tracking an unmanned Army surveillance blimp that tore loose from its ground tether in Maryland and is drifting north over Pennsylvania.

Details are sketchy, but a statement from the North American Aerospace Defense Command in Colorado says the blimp detached from its station at Aberdeen Proving Ground, Maryland, about 12:20 p.m. EDT.

Two F-16 fighter jets from the Atlantic City Air National Guard Base in New Jersey are monitoring the craft.

FAA officials are working with the military to ensure air traffic safety in the area.

The aircraft is known as a Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System and can be used as part of a missile-defense system.

It's not immediately clear how the blimp came loose.