Hackers and cyber terrorists pose a major threat to U.S. economic stability, said PNC Financial Services CEO James Rohr.

Defense Secretary Leon Panetta recently warned the country risks a “cyber-Pearl Harbor.”

Rohr told CNBC Internet hackers have already targeted his financial institution adding that hackers “just pummeled us.”

Editor's Note: The ‘Unthinkable’ Could Happen — Wall Street Journal. Prepare for Meltdown

“We had the longest attack of all the banks,” Rohr told the network.

The bank shielded its data from the attack and lost nothing though the bank’s processes slowed.

“If you have a cyber attack that totally disrupts our banking industry, or if you think about an attack that somehow disrupts our power grid, you could really disrupt this country,” Rohr said, CNBC added.

“Those are the two vulnerabilities that I worry about.”

“We spend a lot more money on security than we ever did before.”

The military is drafting a new plan of attack to deal with cyber threats and those who harbor those responsible, Panetta announced recently.

“We won’t succeed in preventing a cyber attack through improved defenses alone,” Panetta said at a Business Executives for National Security awards dinner.

“If we detect an imminent threat of attack that will cause significant, physical destruction in the United States or kill American citizens, we need to have the option to take action against those who would attack us to defend this nation when directed by the president,” Panetta said.

“For these kinds of scenarios, the department has developed the capability to conduct effective operations to counter threats to our national interests in cyberspace.”

Editor's Note: The ‘Unthinkable’ Could Happen — Wall Street Journal. Prepare for Meltdown