Quick advances in cyber war technologies could soon lead to a new generation of so-called "intelligent cyber weapons" which top global IT defence experts warn could be virtually unstoppable.

"Rapid developments in cyber (technology) might lead to intelligent cyber weapons that are hard to control and it's practically impossible to use formal methods of verifying the safety of intelligent cyber weapons by their users," Enn Tyugu, IT expert at Tallinn's NATO Cyber Defence Centre said at its fourth annual conference Thursday.

He also warned that programmes developed to counter attacks by malwares like Stuxnet can act independently and could possibly themselves spark conflicts.

"They are quite autonomous, and can operate independently in an unfriendly environment and might at some point become very difficult to control... that can lead to cyber conflict initiated by these agents themselves," Tyugu said.

"Stuxnet and Flame have shown the side of cyber of which the average user does not think of but which will bring a lot of challenges to all experts who deal with critical infrastructure protection issues - IT experts, lawyers, policy makers," Ilmar Tamm, Head of the NATO Cyber Defence Centre told AFP Thursday.

"The number of cyber conflicts keeps rising and it is important to understand who the actors in these events are, how to classify these events and participants, and how to interpret all that," Tamm said, noting Western leaders have been slow to become aware of even existing cyber threats.

Experts at the conference noted that both China and Russia have significantly upgraded their cyber-defence capabilities in recent years by creating new IT units.

"But the most powerful weapon today in cyber space is still the propaganda, the chance to use the Internet to spread your message," Kenneth Geers, US cyber defence expert told some 400 top IT gurus attending the meeting Thursday.

Keir Giles, head of Oxford University's Conflict Studies Research Centre, noted that some Russian leaders seemed to "sincerely believe that the recent opposition rallies after the presidential elections in Russia were initiated by the US in cyberspace."