The cyber battlefield is already “very active,” with many nations and nonstate groups displaying offensive and defensive cyber capabilities, a senior Army intelligence officer said.

Speaking at the Aspen Security Forum in Colorado, Army Lt. Gen. Robert Ashley Jr., the Defense Intelligence Agency director, said he’s concerned that in a world filled with systems that are connected by the internet, the level of oncoming reconnaissance “creates a degree of vulnerability.”

“Cyber defense is absolutely critical,” Ashley said. “Whether it is in the military realm, whether it is infrastructure, power grids, banks, the cyber net of things or the internet of things can reach into all kinds of areas. When people ask me, ‘So, what keeps you up at night?’ that is kind of what keeps me up at night.”

His worry is based in part on the fact that major military movements of sea, air or ground forces can be tracked nearly instantaneously, adding “a degree of complexity in future war.”

Anything connected to the internet can be used to gather information, Ashley said. The National Security Agency gives briefings on the subject that “literally will make you throw away your phone on the way out,” said Ashley, who has served as DIA director since October 2017.