Media playback is unsupported on your device Media caption The high-tech US military blimp came loose from its moorings

A US military blimp designed to detect a missile attack that came loose from its mooring is on the ground and secure, state police say.

The aerostat landed in Muncy, Pennsylvania, after floating for three hours with two fighter jets on its tail.

The blimp caused about 18,000 power outages as it dragged its tether line, taking down electricity cables.

It is not known how the 200ft-long (61m) aircraft came loose in Maryland.

Known as a Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System (JLENS), it has been criticised by privacy advocates.

Image copyright AP Image caption The blimp was spotted west of Jerseytown, Pennsylvania

Image copyright Reuters Image caption The blimp landed in Pennsylvania after causing thousands of power outrages

A recent investigation by the Baltimore Sun found the programme had been "hobbled by defective software, vulnerability to bad weather and poor reliability".

Two Twitter parody accounts - one which had been tweeting as the blimp for several years - reacted quickly.

"Peace out losers," one said.

Image copyright ABC

The blimp system is also used in the Iraq and Afghanistan wars to provide ground surveillance around US bases and other sensitive sites.

"My understanding is, from having seen these break loose in Afghanistan on a number of occasions, we could get it to descend and then we'll recover it and put it back up," Defence Secretary Ash Carter told reporters. "This happens in bad weather."