The U.S. government is becoming increasingly concerned that hacker group Anonymous could soon have the ability to take down parts of the power grid, has confirmed.

This view was conveyed by the head of the secretive NSA or National Security Agency, Keith Alexander, during a series of assessments for the White House.

The NSA, one of the intelligence agencies under the Defense Department charged with the collection and analysis of foreign communications and foreign signals intelligence, declined requests for comment.

While China and Russia are seen as more capable of bringing about an outage – Anonymous is increasingly geared toward disruptive actions and officials believe it won't be long before they can bring about a "limited power outage."

It has so far relied on distributed denial-of-service attacks (DDoS), which brings websites crashing down by inundating them with requests. The group was recently blamed for such an attack on the CIA website, slowing service.

U.S. officials insist the incident did not compromise classified information.