UPDATE | Rogue military blimp now secure in Pa.

MUNCY, Pa. (AP) — An unmanned Army surveillance blimp broke loose from its moorings in Maryland and floated over Pennsylvania for hours today with two U.S. fighter jets on its tail, triggering blackouts across the countryside as it dragged its cable across power lines.

The bulbous, 240-foot helium-filled blimp finally came down near Muncy, a small town about 80 miles north of Harrisburg.

The North American Aerospace Defense Command in Colorado said the blimp detached from its station at the military's Aberdeen Proving Ground in Maryland about 12:20 p.m. and drifted northward, climbing to about 16,000 feet.

The F-16s were scrambled from a National Guard base at Atlantic City, N.J., according to NORAD. At the Pentagon, Defense Secretary Ash Carter did not say what the two fighter jets might be asked to do or whether he considered it a threat to aviation.

Witnesses reported seeing the blimp drifting in a sparsely populated area. Its tether was snapping power lines.

The local electric utility, PPL, reported about 20,000 customers without power in the area, and Bloomsburg University canceled classes because of the outage.