A three-week wave of massive cyber-attacks on the small Baltic country of Estonia, the first known incidence of such an assault on a state, is causing alarm across the western alliance, with Nato urgently examining the offensive and its implications.

While Russia and Estonia are embroiled in their worst dispute since the collapse of the Soviet Union, a row that erupted at the end of last month over the Estonians' removal of the Bronze Soldier Soviet war memorial in central Tallinn, the country has been subjected to a barrage of cyber warfare, disabling the websites of government ministries, political parties, newspapers, banks, and companies.

Nato has dispatched some of its top cyber-terrorism experts to Tallinn to investigate and to help the Estonians beef up their electronic defences.

"This is an operational security issue, something we're taking very seriously," said an official at Nato headquarters in Brussels. "It goes to the heart of the alliance's modus operandi."

Interesting. This is the first I've heard of this.

If it were established that Russia is behind the attacks, it would be the first known case of one state targeting another by cyber-warfare.

I'm not so sure about that part... I guess it depends on how you define cyber-warfare. I prefer to view this all as different flavors of information warfare, which very much includes espionage activity, which we have often seen.

The crisis unleashed a wave of so-called DDoS, or Distributed Denial of Service, attacks, where websites are suddenly swamped by tens of thousands of visits, jamming and disabling them by overcrowding the bandwidths for the servers running the sites. The attacks have been pouring in from all over the world, but Estonian officials and computer security experts say that, particularly in the early phase, some attackers were identified by their internet addresses - many of which were Russian, and some of which were from Russian state institutions.

"The cyber-attacks are from Russia. There is no question. It's political," said Merit Kopli, editor of Postimees, one of the two main newspapers in Estonia, whose website has been targeted and has been inaccessible to international visitors for a week. It was still unavailable last night.

At the moment, the big question may be if this type of attack qualifies as a military action in the same way that electronic warfare does. At this point, if only websites are being DoS'd, it's one thing. If the attacks are (or become) focused on key infrastructure, it would be more clear cut. If these attacks are driven by state conflicts, this is a dangerous grey area to play in.

Without more information, it is very hard to determine if these attacks are backed by the state, or just being done by rogue hackers that happen to be motivated by the row between Russia and Estonia.