"Our systems register over 500 million suspicious cyber events each day," NATO spokesperson Oana Lungescu told CNN Thursday.
She added that in 2016, NATO was subjected to an average of 500 cyberattacks per month that merited some kind of response, "an increase of roughly 60% over 2015."
"Foreign governments, criminals and terrorists can all be the source of cyberattacks, and attribution can be difficult," Lungescu said. "But of course, nations have the largest resources in the cyber field, and they are responsible for the majority of targeted attacks against NATO networks."
President-elect Donald Trump called the military alliance obsolete in an interview with British and German media that was published on Sunday.
"I said a long time ago that NATO had problems," Trump told them. "It was obsolete, because it was, you know, designed many, many years ago."
But at the Davos Forum in Switzerland Thursday, NATO Secretary General emphasized the alliance's adaptability in the face of new threats like cyber.
He noted that the alliance would respond to cyber-attacks in the same way that it would to a conventional assault, making cyber eligible for the invocation of NATO's mutual defense clause, Article V.
In June, NATO opted to make cyber an official operational domain of warfare, along with air, sea and land.
"We have decided that a cyberattack can trigger Article Five, meaning that (a) cyberattack can trigger a response from the whole alliance as a conventional armed attack," Stoltenberg said.
"We are doing more when it comes to cyber defense because we have to understand that cyber-attacks can be as dangerous, as serious as armed attacks," he said.
NATO officials have said that the alliance already faces daily attacks from a variety of hostile actors.
Russia is widely believed to have the most sophisticated cyber capabilities among NATO's traditional adversaries.
Stoltenberg's comments on cyber come amid increased concerns over security following the US intelligence community's findings that Russia directed cyber attacks against US electoral organizations.
US officials have also warned that Russia may mount similar cyber campaigns against targets in Europe.
Speaking at NATO headquarters in Belgium last week, the secretary general warned adversaries against meddling in elections.
"We have seen reports about cyberattacks against many NATO allies and any attempt to intervene or to influence national elections from outside is unacceptable," he said.
Throughout his appearance at Davos, Stoltenberg repeatedly touted the alliance's ability to respond and adapt to an ever-changing security environment, citing NATO's moves to bolster its eastern flank, fight terrorism in Afghanistan and respond to cyber.
"NATO is the most successful military alliance in history because we have been able to adapt and will continue to adapt," Stoltenberg said.