Vladimir Putin has said that a western move to let Kyiv use longer-range weapons against targets inside Russia would mean Nato would be “at war” with Moscow. Putin spoke as US and UK top diplomats discussed easing rules on firing western weapons into Russia, which Kyiv has been pressing for, more than two and a half years into Moscow’s offensive. “This would in a significant way change the very nature of the conflict,” Putin told a state television reporter. “It would mean that Nato countries, the US, European countries, are at war with Russia,” he added. “If that’s the case, then taking into account the change of nature of the conflict, we will take the appropriate decisions based on the threats that we will face.” Clearing Kyiv to strike deep into Russia “is a decision on whether Nato countries are directly involved in the military conflict or not”. Putin’s comments came a day after the US secretary of state, Antony Blinken, gave his strongest hint yet that the White House is about to lift its restrictions on Ukraine using long-range weapons supplied by the west on key military targets inside Russia. Speaking in Kyiv alongside the UK foreign secretary, David Lammy, Blinken said the US had “from day one” been willing to adapt its policy as the situation on the battlefield in Ukraine changed. “We will continue to do this,” he emphasised. Blinken said he and Lammy would report back to their “bosses” – Joe Biden and Keir Starmer – after their talks on Wednesday with the Ukrainian president, Volodymyr Zelenskiy. The foreign secretary suggested that Iran’s dispatch of ballistic missiles to Moscow – revealed this week – had changed strategic thinking in London and Washington. It was a “significant and dangerous escalation”, he said. He added: “The escalator here is Putin. Putin has escalated with the shipment of missiles from Iran. We see a new axis of Russia, Iran and North Korea.” Lammy urged China “not to throw in its lot” with what he called “a group of renegades”. British government sources indicated that a decision had already been made to allow Ukraine to use Storm Shadow cruise missiles on targets inside Russia, although it is not expected to be publicly announced on Friday when Starmer meets Biden in Washington DC. The two leaders are planning to discuss the war in Ukraine, and how it could be ended, as part of a wide-ranging foreign policy discussion, though they will avoid an intense focus on any individual weapons system, as the focus of the conversation is strategic.