WASHINGTON (AP) – The Defense Department is establishing a series of cyber teams charged with carrying out offensive operations to combat the threat of an electronic assault on the United States that could cause major damage and disruption to the country’s vital infrastructure, a senior military official said Tuesday.

Gen. Keith Alexander, the top officer at U.S. Cyber Command, warned during testimony that the threat of an electronic assault against the nation’s electric grid and other essential systems is real and more aggressive steps need to be taken by the federal government and the private sector in order to improve digital defenses.