Neb. Rev. Stat. § 72-701.02

As used in sections 72-701.01 to 72-701.06 , the term attack means any action or series of actions by an enemy of the United States, causing, or which may cause substantial injury or damage to civilian persons or property in the United States in any manner, whether by sabotage, or by the use of bombs, missiles or shellfire, or by atomic, radiological, chemical, bacteriological or biological means, or by other weapons or processes.