Some analysts see "cyber war" an emerging global security risk
Seven Nato nations have backed a new cyber defence centre in Estonia, which last year blamed Russia for weeks of attacks on its internet structure.
Germany, Slovakia, Latvia, Lithuania, Italy and Spain will staff and fund the hub in the Estonian capital Tallinn.
Estonia came under cyber attack in 2007 after its decision to remove the bronze statue of a Red Army soldier from the centre of Tallinn.
Moscow denied involvement in the flood of data which crashed computers.
"We have seen in Estonia that a cyber attack can swiftly become an issue of national security," Nato spokesman James Appathurai said after a signing ceremony in Brussels.
"Cyber attacks can cripple societies."
The US will initially send an observer to the project, which will have some 30 staff when fully operational in August.
The centre will provide research, consultation and training on the development of cyber defences for participating national governments.