The nation's top counterintelligence officer said at a Minneapolis Cyber Security conference in Minneapolis last week that he's most concerned about external cyber threats against critical U.S. infrastructure.

William R. Evanina is a veteran CIA and FBI operative and director of the National Counterintelligence and Security Center (NCSC), and chief security adviser to his third director of national intelligence since 2014.

Evanina, in an interview during the annual Cyber Security Summit for business and government attendees, listed Russia, China, Iran and North Korea as the leading threats in the business of computer weaponization against U.S. targets.

"I'm concerned about [our] ability to protect critical infrastructure … utilities, transportation, the financial system and telecommunications from state-sponsored intelligence services and various nonstate actors," he said. "The lights are blinking red.

"We are in dire need to ensure the most effective public-private partnerships to understand the threat surface and position ourselves. Most of the threat surface the government doesn't own."

Evanina added that there has been "significant progress" and "great partnerships" formed in recent years to deter and counteract cyber enemies.

Under Evanina, NCSC produces the National Counterintelligence Strategy of the United States of America, which has attempted to raise the "foreign intelligence threat awareness,"and close "critical CI and security gaps in the executive branch and agencies."

Before being named director of the NCSC, Evanina was chief of the CIA's counterespionage group, where he led intelligence community agencies in identifying, preventing and neutralizing espionage-related activities by foreign intelligence services.

Evanina reported to Dan Coates, direct of national intelligence, who departed last summer over differences with President Donald Trump.