Russian President Vladimir Putin could seek to test Nato’s resolve by launching a limited attack against a member of the alliance in the coming years, according to recent US intelligence assessments cited by CNN.The assessments warn that Moscow could explore several forms of escalation, ranging from a cyberattack to a limited military incursion designed to challenge Nato’s unity and its commitment to collective defence. The objective, according to three people familiar with the intelligence, would not necessarily be to trigger a full-scale confrontation, but to test how far the alliance would go to defend one of its members.Under Nato’s Article 5, an armed attack against one member is treated as an attack against all. But US intelligence believes Putin could try to operate below the threshold that would force Nato into a major military response, potentially exposing divisions within the alliance.One of the sources told CNN that the Baltic states or Poland could be among the most likely targets if Russia chooses to escalate. The exact timing and form of any such move remain uncertain, with the window for potential escalation stretching from now into the next several years.US and Nato officials believe Russia could become more willing to challenge the alliance if Putin fails to secure what he considers a face-saving way out of the war in Ukraine, CNN reported.The warning comes amid growing concerns in Europe that Russia could rebuild its military strength once the fighting in Ukraine ends. Last month, the Dutch defence ministry warned that Moscow was preparing for a prolonged confrontation with Europe and, in a worst-case scenario, could be capable of a limited war against a Nato member within a year of the Ukraine war ending.The Dutch assessment said Russian military preparations pointed towards a long-term confrontation with Europe. Nato Secretary General Mark Rutte has also previously warned that Russia could be ready to use military force against the alliance within five years.Concerns are not limited to a future scenario. Nato countries have already faced incidents involving Russian drones and suspected sabotage. In September, Nato aircraft shot down Russian drones that entered Polish airspace during a Russian attack on Ukraine. In May, a drone carrying explosives struck an apartment building in Romania while Russian forces attacked a nearby Ukrainian port, injuring two people.CNN also reported this week that US officials believe an explosive-laden drone discovered at an airport in Germany belonged to a Russian intelligence service.Nato has sought to strengthen its deterrence as these incidents mount. Martin O’Donnell, a senior Nato military spokesperson, declined to comment on classified intelligence but told CNN that the alliance was “always thinking through and preparing for any number of scenarios”.“Nato is watching and we are ready to deter and defend as necessary,” he said.The latest intelligence assessment suggests the central challenge for Nato may not simply be preventing a Russian attack, but ensuring that any attempt by Putin to test the alliance does not expose cracks in its collective defence.