Two decades on from the end of the cold war, Nato governments returned last night to their core mission of protecting Europe from Russia.
As a result of the Kremlin's seizure of Ukraine's Black Sea peninsula of Crimea, Nato foreign ministers discussed plans to bolster defences in eastern Europe and suspend "all practical civilian and military co-operation" between Nato and Russia", Nato officials said.
The foreign ministers also acted to boost military co-operation with former Soviet states on Russia's southern flank.
However, the first Nato ministerial meeting since Moscow annexed Crimea shied away from stationing Nato forces permanently in eastern Europe and from contemplating Nato membership for Ukraine.
While Moscow declared that the seizure of the Ukrainian peninsula had nothing to do with Russia but rather had occurred as a result of "internal processes" in Ukraine, Nato leaders dismissed assurances from the Kremlin of a pull-back of forces, estimated at 40,000, massing on Ukraine's eastern borders.
"Unfortunately, I cannot confirm that Russia is withdrawing its troops. This is not what we have seen," said Anders Fogh Rasmussen, the Nato secretary general.
The British foreign secretary, William Hague, said: "We have heard some statements or rumours that Russia was pulling back from the eastern border of Ukraine, but we haven't seen the evidence of that yet."
"The concentration of troops along the Ukraine border is very high," said Angela Merkel, the German chancellor.
The meeting discussed military aid for Kiev, reinforced defences for "frontline" Nato states in Poland and the Baltic, planned to extend military co-operation to Moldova, Azerbaijan and Armenia – all former Soviet republics on Russia's southern flank – and froze military and civil co-operation with Russia.
"Our goal of a Euro-Atlantic region whole, free and at peace has not changed but has been fundamentally challenged by Russia," said a Nato statement. "Over the past 20 years, Nato has consistently worked for closer co-operation and trust with Russia. It has gravely breached the trust upon which our co-operation must be based."
Poland voiced exasperation with delays in strengthening Nato's eastern borders and with the reluctance to base Nato forces there. The topic has been taboo since Nato's expansion into eastern Europe in the 1990s for fear of antagonising Russia.
Rasmussen ruled out any quick decisions on this, calling instead for diplomacy and dialogue with Russia and Ukraine. Frank-Walter Steinmeier, the German foreign minister, said he saw no prospect of drawing Ukraine or any other former Soviet state into Nato.
Donald Tusk, the Polish prime minister, voiced disappointment, while his foreign minister, Radek Sikorski, called for two Nato brigades to be stationed in Poland.
"The pace of Nato increasing its military presence for sure could be faster," said Tusk. "This is a unsatisfactory result for us."
In advance of yesterday's meeting, a Nato committee drafted plans "for promoting stability in eastern Europe in the current context" by boosting military co-operation with Armenia, Azerbaijan, and Moldova, all in Russia's "near abroad" and viewed by a proprietorial Moscow as falling within its sphere of influence.
A confidential seven-page paper leaked to the German news weekly Der Spiegel proposed joint exercises and training between Nato and the three countries, increasing the "interoperability" of their militaries with Nato and their participation in Nato "smart defence" operations.
The paper also proposed opening a Nato liaison office in Moldova, providing military training for Armenia, and undertaking projects in Azerbaijan aimed at securing its Caspian Sea oil- and gasfields.
Nato and EU member states such as Poland and the three Baltic countries on the frontline of the new frictions with President Vladimir Putin are alarmed at Russia's expansionist policies, amid widespread suspicions that Moscow will seek to destabilise and coerce Moldova prior to its scheduled signing in June of a trade and political pact with the European Union.
The US has responded to the pleas from eastern Europe by reinforcing Nato air patrols over the Baltic and dispatching aircraft to Poland. The foreign ministers discussed contributing to the precautionary moves, with Britain, Denmark and Germany offering to supply more air power.
"We should do everything we can to reassure our friends and colleagues in Latvia, Lithuania and Estonia and in Poland that we really believe in their Nato membership and the guarantees that we have given them," said David Cameron.
Nato's supreme commander in Europe, the US general Philip Breedlove, warned at the weekend that the Russian buildup was "very, very sizeable and very, very ready".
He added that the Kremlin could move to seize Transnistria, a Russian-speaking part of Moldova that has been locked in a "frozen conflict" and effectively controlled by the Russians since the 1991 collapse of the Soviet Union.
While Barack Obama has declared that Nato must respond to the Russian force with "strength and conviction", there is a sense among Nato diplomats that the Kremlin's strategy has reinforced Nato's raison d'être , boosting the arguments for its continued existence against regular calls for its dissolution as a cold war relic.
