A hi-tech US military blimp broke loose from its mooring and floated away with two US fighter jets in pursuit, officials said.
The JLENS aerostat, which is nearly the length of a football field, detached from its mooring in Maryland, the North American Aerospace Defense Command (NORAD) said in a statement.
Two F-16 fighter jets monitored the helium-filled blimp as it floated northeast of Washington at an altitude of 4,875 metres.
The blimp, equipped with radar to help detect a missile attack on the US capital, later landed in Pennsylvania, a county emergency management official said.
"It is down in Montour County," said John Thomas, a spokesman for the Columbia County emergency management agency.
Mr Thomas said there were no immediate reports of injuries or damage from the grounding, though he said the blimp's wayward journey has left thousands of people without power.
JLENS blimps carry powerful radars that can protect large areas from airborne threats including unmanned aircraft, cruise missiles and other objects.
