Estonia decided to remove a Soviet-era monument from its capital city. Putin apparently wasn’t amused.

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.”

Because it’s not an actual armed attack and because Russia hasn’t been definitively linked to the cyber attacks yet (though it’s a near certainty that Russia is behind it), this doesn’t invoke Article V of the NATO treaty, in which an attack on one is treated as an attack on all. But NATO is in the game and the Estonians aren’t laying down.

With their reputation for electronic prowess, the Estonians have been quick to marshal their defences, mainly by closing down the sites under attack to foreign internet addresses, in order to try to keep them accessible to domestic users.

The cyber-attacks were clearly prompted by the Estonians’ relocation of the Soviet second world war memorial on April 27.

Ethnic Russians staged protests against the removal, during which 1,300 people were arrested, 100 people were injured, and one person was killed.

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.

We’re not in a new Cold War with Russia yet, at least according to our own Secretary of State, but if Russia is behind the first state-on-state cyber war, and if as it seems to be that Russia was behind the murder of Alexander Litvinenko, and it’s obvious that Russia is playing a deep game with respect to its involvement in Iran’s nuclear program, and as Russia has been playing hardball with former satellites Ukraine and Georgia, we will be in a new Cold War with Russia soon. Under Putin, Russia appears to be going in the direction of rogue state.