Nato chief Jens Stoltenberg said on Thursday that the alliance is coming under an increasing number of state-sponsored cyber attacks, as he called on the bloc to boost its online defence capabilities.
"According to our latest evaluations, there was a monthly average of 500 threatening cyber attacks last year against Nato infrastructure that required intensive intervention from our experts," he told Die Welt daily.
"That's an increase of 60% compared to 2015. Most of these attacks did not stem from private individuals but were sponsored by national institutions of other countries," he added.
Voicing deep concerns about the development, Stoltenberg said cyber defence will play a key role at the next Nato summit.
"We must boost our capabilities in this area," he said, warning that attackers can "damage the defence readiness of Nato and hinder the work of our armed troops".
"All military activities are now based today on data transmission. If that fails to work, it can cause serious damage," he said.
Several Western nations including Britain, France and Germany have warned of a rise in cyber attacks, and are boosting their defence infrastructure to cope with the new front.
While Stoltenberg did not name the states responsible for the attacks against Nato, Germany has on several occasions fingered Russia as a culprit -- accusations that Moscow denies.
In the interview published on Thursday, Stoltenberg also rejected Donald Trump's criticism of the alliance's fight against terror and shrugged off the US president-elect's claim that Nato was "obsolete".
"Nato is already strongly engaged in the fight against international terrorism, and we are discussing how this engagement can be broadened," Stoltenberg said.
The Nato chief added that he is looking forward to working with Trump, and voiced confidence that "the US will continue to be fully committed to its security guarantees for Nato."