Munich Security Conference (MSC) in Munich
NATO Secretary General Jens Stoltenberg speaks, during the Munich Security Conference (MSC) in Munich, Germany February 18, 2023. Reuters

The war in Ukraine must bring an end to "a cycle of Russian aggression" that goes back much further than the invasion Moscow launched a year ago, NATO Secretary-General Jens Stoltenberg said on Thursday.

In an interview with Reuters on the eve of the first anniversary of Moscow's attack, Stoltenberg said the invasion was part of a pattern that included Russian military action in Georgia in 2008 and Donbas and Crimea in Ukraine in 2014.

"We don't know when the war will end. But what we do know is that when the war ends, we need to ensure that history doesn't repeat itself," Stoltenberg said.

"We need to ensure that we break the cycle of Russian aggression. We need to prevent Russia from chipping away at European security," he told Reuters at NATO's glass-walled headquarters on the outskirts of Brussels.

He said this meant ensuring that "Ukraine has the military capabilities, the strength to deter further aggression."

Beyond providing Ukraine with munitions to help repel Russia's invasion, NATO allies have also begun talking to Kyiv about a longer-term partnership, Stoltenberg said.

This included helping Kyiv to modernize its defence and security institutions and to move from Soviet-era equipment, doctrines and standards to their NATO equivalents, he said.

Russia sent tens of thousands of troops over its border into Ukraine last year in what it called a "special military operation" saying it was countering threats to its own security.

It has regularly disputed assertions by the West, Kyiv and Tbilisi about its military actions, saying it intervened in Georgia to protect people in disputed regions there.

It denied backing separatists in Ukraine's Donbas region in 2014 and said its annexation of Crimea was backed by a referendum, which Kyiv and the West say violated Ukraine's constitution and international law.

'UNREAL EXPERIENCE'

Recalling the day President Vladimir Putin sent Russian forces into Ukraine last year, Stoltenberg said the huge significance of the moment was immediately clear.

Even though NATO had received and widely shared intelligence warnings that Moscow would invade, Stoltenberg said it was still an "unreal experience" to see "more than 100,000 troops entering a democratic, free independent country in Europe."

"This is now the biggest security crisis, the biggest war we have seen since the Second World War," said Stoltenberg, 63, a former prime minister of Norway who has been NATO chief since 2014.

"We all realised that day that there was a Europe, there was a world, before and a world after Feb. 24," he said.

NATO members, led by the United States, have provided billions of dollars of arms and ammunition to Ukraine, supplying increasingly advanced weapons systems as the war has gone on.

NATO has also sent thousands more troops to eastern Europe as alliance members there fear they could be Moscow's next target.

Stoltenberg said NATO members were working to both support Ukraine and to prevent the conflict escalating to become a "full-fledged war between Russia and NATO".

"That's the reason why we have significantly increased our military presence in the eastern part of the alliance, to send a very clear message to Moscow that an attack on one ally will trigger a response from the whole alliance," he said.

"This is not to provoke a conflict but to prevent a conflict, to preserve peace, and to remove any room for miscalculation in Moscow," he added.

Stoltenberg has led NATO through tumultuous times, including the U.S. presidency of Donald Trump, whose criticism of the alliance cast doubt on Washington's commitment to NATO, and also during the withdrawal of U.S. and NATO forces from Afghanistan.

Having had his tenure extended three times, he declared this month he had no intention of seeking a further extension when his current term finishes at the end of September this year.

Asked if he might still be open to a further extension if NATO member countries asked him to accept one, he said: "I have nothing more to say about that beyond what I've already said."