NATO leaders united today behind a "hard-headed" policy of deterrence and dialogue with Russia after launching the alliance's biggest military revamp since the Cold War to counter a resurgent Moscow.
Alliance chief Jens Stoltenberg said alliance leaders "stand together" on Russia, agreeing at a summit in Warsaw to bolster its eastern flank after Moscow's annexation of Crimea and the Ukraine conflict.
Russian President Vladimir Putin has opposed NATO's decision to put four battalions in Poland and the Baltic states, seeing the expansion into Moscow's Soviet-era backyard as a direct security threat.
"The alliance is united, we stand together," Stoltenberg said when asked about the leaders' talks on Russia. "The united message is that defence and dialogue are what our relationship is based on."
Around 200 anti-war activists defied heavy security in central Warsaw to protest against the summit, carrying banners saying "Yes to Peace, No to NATO", AFP journalists saw.
Unity was the buzzword of the two-day summit in the Polish capital after Britain's shock vote to quit the European Union raised questions about its future role as a nuclear armed global power.
Prime Minister David Cameron reassured his peers that Britain was committed to the alliance and announced a parliamentary vote on July 18 on revamping Britain's Trident nuclear deterrent to back that up.
"The nuclear deterrent remains essential in my view not just to Britain's security but as our allies acknowledge here today to the overall security of the NATO alliance," Cameron told a news conference.
Cameron said Britain fully backed the measures adopted by NATO in response to the Ukraine crisis "but we must also engage in a hard headed dialogue with Russia".
NATO's two-track strategy reflects underlying divisions in the bloc, with calls from France and Germany to avoid a Cold-War style stand-off when Moscow's help is needed on issues such as terrorism.
The United States and European Union have both imposed sanctions on Moscow over the Ukraine crisis but in Europe in particular there are growing calls for them to be scaled back.
French President Francois Hollande appeared to offer an olive branch to Moscow, saying yesterday Russia was neither adversary nor threat but a partner.
Leaders will discuss Ukraine with President Petro Poroshenko later today.
Stoltenberg announced earlier this week that the alliance would hold a fresh meeting with Russia on Wednesday as a gesture of the West's openness and good faith.
Eastern European states have previously warned against easing the pressure, but NATO's unprecedented new measures have begun to reassure them.
Lithuanian President Dalia Grybauskaite, a sharp critic of Putin, said a stronger NATO would be better able to talk to Russia.
