European intelligence chiefs are warning that Russia could intensify hostile action against NATO “within months, not years”, closely echoing concerns raised by Polish Prime Minister Donald Tusk in the Sejm just days earlier.
Tusk told MPs on 17 September that intelligence available to Poland indicated Moscow may be preparing hybrid drone and missile strikes against countries supporting Ukraine, including Poland, potentially presented as “accidental” incidents intended to weaken NATO’s willingness to invoke its collective-defence mechanisms.
Now, senior European intelligence officials interviewed by The Guardian have issued a strikingly similar assessment.
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They warned that Russia may be moving towards more decisive action against NATO, ranging from sabotage and psychological operations to drone or missile attacks and potentially even a limited military incursion designed to test the credibility of Article 5. One intelligence official said the timeframe should be thought of in terms of “months, not years”.
The overlap with Tusk’s warning is significant because the Polish prime minister had already described the intelligence picture as becoming increasingly coherent and convincing.
Tusk warned of ‘hybrid strikes’ days earlier
Speaking in parliament on Thursday, Tusk said Poland had been receiving information from its own services, NATO allies and Ukrainian partners about Russia’s evolving strategy.
“In the assessment of the intelligence services, the Russian plan also includes hybrid drone and missile strikes against countries supporting Ukraine, including Poland,” he said.
Tusk added that such incidents could be deliberately framed as accidental.
BREAKING: Poland and Ukraine averted a “direct threat” to one of their shared border crossings overnight, Polish PM @donaldtusk said after a Visegrád Group meeting in Bratislava.
— Poland 24 🇵🇱 (@poland24com) September 10, 2026
“We expect similar actions targeting border crossings with Ukraine in other countries, including… pic.twitter.com/NzXOYBppWS
He warned that drones or other projectiles could enter NATO territory, potentially causing damage, while Moscow would maintain that no deliberate attack had taken place.
The purpose, he said, could be to “paralyse or at least weaken” NATO countries’ motivation to apply alliance procedures in response to aggression.
That concern goes directly to the credibility of Article 5, the NATO principle under which an armed attack against one member is considered an attack against all.
The Polish government summarised Tusk’s position by saying Russia’s objective was to weaken NATO’s integrity and undermine faith in Article 5.
European services now voice similar concern
The Guardian’s new reporting suggests Tusk’s warning is not an isolated Polish assessment.
Intelligence officials across Europe told the newspaper that Russia appeared to be preparing for more aggressive activity against NATO, even while its conventional military remains heavily committed in Ukraine.
The possible scenarios described include drone and missile attacks, sabotage, covert operations and a deliberately limited confrontation intended to create uncertainty about whether NATO would respond collectively.
The warnings stop well short of saying that Moscow has decided to launch a full-scale attack on Poland or another NATO country.
Instead, the concern is that the Kremlin may be willing to accept greater risk and test the alliance below the threshold of all-out war.
That distinction is also consistent with Tusk’s remarks.
He did not tell the Sejm that a conventional invasion of Poland was imminent. He warned instead about ambiguous attacks that could be portrayed as mistakes and used to probe NATO unity.
‘Months, not years’
The phrase used by one European intelligence official — “months, not years” — gives the latest warnings particular urgency.
Tusk had already spoken in similarly near-term language.
Following a Russian attack close to the Polish-Ukrainian border on 13 September, he said the “coming weeks and months” were likely to bring intensified Russian activity and warned that escalation affecting Polish territory could not be ruled out.
Four days later, he told parliament that late autumn and winter could become the most critical period of the war so far.
The convergence between those warnings and the assessments now being voiced by European intelligence officials makes the issue broader than a Polish domestic security debate.
It suggests several European capitals are working with broadly similar assumptions about the possibility of more aggressive Russian pressure on NATO’s eastern flank.
Poland particularly exposed
Poland is especially relevant to those assessments because of its geography and role in supporting Ukraine.
It borders Ukraine, Belarus and Russia’s Kaliningrad region, hosts allied NATO forces and acts as one of the principal logistical routes for military and humanitarian support to Kyiv.
Its north-eastern frontier also contains the Suwałki Gap, the narrow corridor connecting Poland with Lithuania and the other Baltic states.
Any attempt to create uncertainty around NATO’s response in Poland or the Baltic region would therefore have consequences far beyond the country directly affected.
Tusk has repeatedly presented that vulnerability as a reason for strengthening both Poland’s own armed forces and allied cooperation.
Russia still constrained by Ukraine war
The intelligence picture is not uniform, however.
Baltic officials have also cautioned against treating war with NATO as inevitable.
Russia still has significant military resources tied down in Ukraine, and there is no publicly available evidence that Moscow has taken a decision to launch a conventional attack on NATO in the immediate future.
That caution matters because fear itself can serve Russian objectives.
European intelligence officials told The Guardian that Moscow’s psychological and influence operations seek to amplify uncertainty, undermine confidence in NATO and weaken public willingness to continue supporting Ukraine.
The warning, therefore, is not that a Russian invasion of Poland is expected within months.
It is that European security services increasingly believe Moscow could move towards a more aggressive phase of confrontation in which the distinction between sabotage, provocation and military attack becomes deliberately blurred.
Tusk’s warning gains wider European backing
That is essentially the scenario Tusk described to the Polish parliament.
His warning centred on Russian attempts to create incidents that appear accidental, test political will and make NATO members hesitate over whether the threshold for collective defence has been crossed.
The new intelligence reporting gives that assessment wider European context.
What was presented in Warsaw last week as Poland’s reading of Russian intentions is now being echoed by intelligence officials elsewhere in Europe: Russia may seek to test NATO not through an immediate large-scale war, but through carefully calibrated action designed to expose uncertainty inside the alliance.
For Poland, the practical consequence is the same one Tusk outlined in the Sejm — preparation for ambiguous threats must now be treated as part of national defence planning, not as a distant hypothetical scenario.
