NATO Secretary-General Jens Stoltenberg said there were 500 dangerous cyber attacks on NATO facilities every month in 2016. The figure represents a 60% increase on the previous year, DW wrote.

In an interview published in Germany's "Die Welt" newspaper on Thursday, Stoltenberg added that most of those assaults on the alliance's data network were "sponsored by state institutions in other countries," rather than by private individuals.

"I am extremely concerned about this development," he said. "Cyber defense will play an important role at the next NATO summit, and we'll need to step up our efforts in this area."

Read alsoFrench military to boost defenses against cyber attacks: ministerStoltenberg warned that cyber attacks can be particularly dangerous if they compromise energy networks, healthcare facilities and other critical infrastructure.

"They can also harm NATO's defense capability and the work of our armed forces," he added. "All military activities are now based on the transmission of data. So if that fails, it can cause serious damage."

Read alsoNATO aware of danger posed by Russia for Europe – MuzhenkoThe former Norwegian prime minister also voiced alarm at the possibility of hackers manipulating data during election campaigns. He said various member states already feared "hackers would try to interfere in national election campaigns, undermining democracy."

NATO has made crisis teams available to its member states to help them safeguard their networks from such attacks, he said.