The US secretary of state, Tony Blinken, has said that a diplomatic resolution to the Ukraine crisis was still possible and preferable, but warned that progress was impossible while Russia continued to escalate pressure along the border. Blinken was speaking after a virtual meeting of Nato foreign ministers and before a week of intensive diplomacy in Europe aimed at fending off a threatened Russian invasion of Ukraine. He said that the US and its allies could talk about “confidence-building measures, greater transparency, [and] risk reduction” with Russia but the treaties Moscow is demanding the US and Nato sign on unilateral troop withdrawal from eastern Europe and ruling out future Ukrainian membership of Nato were “non-starters”. Jens Stoltenberg, the Nato secretary general, also vowed that Nato would never withdraw its conditional offer of membership to Ukraine, arguing the true threat to Russia was Ukraine’s secure democratic politics. Blinken accused Russia of “gaslighting” the world with its claim that Nato and Ukraine were threatening Moscow rather than the other way around. “No one should be surprised if Russia instigates a provocation or incident then tries to use it to justify military intervention, hoping that by the time the world realises the ruse it’ll be too late,” he said. The secretary of state pointed out that Russia had massed 100,000 troops around Ukraine with “plans to mobilise twice that number on very short order”. NBC News reported on Friday that the US was willing to negotiate a mutual withdrawal of troops, with Russia pulling back from the Ukrainian border and the US withdrawing forces from Nato’s eastern flank. The administration “is compiling a list of options for force posture changes in Europe to discuss with Russia at the talks”, an administration official told NBC. The US state department spokesperson Ned Price later denied the NBC report, saying: “It is not accurate that the administration is developing options for pulling back U.S. forces in Eastern Europe in preparation for discussions with Russia next week.” Blinken did not go into details but said there were areas “where if Russia has legitimate concerns, we’re fully prepared to listen, to engage and to see if we can make progress”. He added that progress could be made “if we approach this as a two-way street based on reciprocity”, but that “actual progress is going to be very difficult to make, if not impossible, in an environment of escalation by Russia”. In his remarks after the Nato ministerial meeting, Stoltenberg said: “The Russian military buildup has not stopped. It is gradually building up with artillery and electronic warfare equipment.” He warned that in the event of a Russian invasion, there would be a major movement of troops to protect Nato countries on the border of Russia. The Nato show of strength was intended as a message to Vladimir Putin that he will be unable to lure the US into any concessions in separate bilateral talks about Ukraine’s sovereignty or Nato’s future structure. Although Stoltenberg said Nato was prepared to discuss issues such as troop transparency, western officials are sceptical that next week’s round of talks will lead to a breakthrough and believe the demands Putin set out on 17 December in the form of two draft treaties have been framed to be rejected. “We are ready to engage in arms control with Russia, conventional and nuclear, but that has to be reciprocal,” Stoltenberg said. “That’s a different thing [from] imposing one-sided restrictions … we can’t end up in a situation where we have second-class Nato members where Nato as an alliance is not allowed to protect them.” Nato is adamant that its conditional offer of membership to Georgia and Ukraine, first made in 2008, will not be withdrawn, even if in practice membership is not imminent. Both countries have been invited to attend part of a meeting of Nato defence ministers next month. The UK foreign secretary, Liz Truss, said: “Russia’s military buildup on the border of Ukraine and in illegally annexed Crimea is unacceptable. There is no justification for its aggressive and unprovoked stance towards Ukraine. “We stand with our Nato allies in urging Russia to end its malign activity and adhere to international agreements it freely signed up to. “We will defend democracy in eastern Europe and around the world. Our support for Ukraine’s sovereignty and territorial integrity is unwavering. We are clear that any Russian incursion would be a massive strategic mistake, for which there would be a severe cost.” UK officials remain unclear whether Putin will invade, but they appear increasingly focused on strengthening forward defences inside Nato. The west has promised massive economic sanctions against Russia if an incursion occurs, but it has ruled out sending troops – as opposed to arms – into Ukraine. The round of talks start on Monday with a bilateral meeting in Geneva between US and Russian officials over future security structures. This will be followed by a meeting in Brussels on Wednesday of the Nato Russian council, the first such meeting for two years, and finally a meeting of the Organization for Security and Cooperation in Europe (OSCE) chaired by Poland in Vienna. Western officials suggested the dispatch of a few thousand Russian troops to suppress the rebellion in Kazakhstan would not alter Putin’s military calculations, even if it represents an unexpected political headache for Moscow. The French foreign minister, Jean-Yves Le Drian, said Putin was trying to discuss with Nato proposals “to sort of return to the zones of influence from the past … which would mean Russia restore the spirit of Yalta” – a reference to the conference between second world war allied powers in February 1945 that gave the Soviet Union control over its eastern European neighbours. “This is not our point of view, but we have to accept the discussion,” Le Drian said.