Army blimp wreaks havoc in Maryland

A hi-tech US military blimp designed to detect a missile attack came loose and wreaked havoc as it floated from Maryland into Pennsylvania while dragging more than 1km of cable and knocking out power to thousands.

The US military scrambled two armed F-16 fighter jets to keep watch as the massive blimp travelled into civilian airspace after coming untethered from its base at Aberdeen Proving Ground, a US Army facility 65km north of Baltimore.

Pentagon officials said they were unsure why the 73m-long blimp broke free.