Two people are dead after a missile struck a farm in Poland near the border with Ukraine on Tuesday evening.
Here’s what we know so far and what it means for Ukraine, NATO and Russia.
Who fired the missile that hit Poland and was it deliberate?
Initial reports suggested that the missile had been fired by Russia at Ukraine and veered off course into Poland.
But Jens Stoltenburg, the secretary general of NATO, said on Wednesday that the alliance’s “preliminary analysis” is that it was more likely a Ukrainian missile deployed to shoot down one of Russia’s many cruise missiles and that it strayed into Polish territory accidentally.
Though he added, “this is not Ukraine’s fault” and that “Russia bears ultimate responsibility as it continues its illegal war against Ukraine”.
What does this mean for NATO?
Poland is a member of the North Atlantic Treaty Organization (NATO), a defence pact between 30 member countries, including nuclear powers, the UK, France and the US.
A strike on Polish soil is therefore a particular concern for Russia and the West. The rules of NATO say that an attack on one member country is an attack on all.
If Tuesday’s missile strike had been a deliberate assault by Vladimir Putin, it could have risked drawing NATO into a direct conflict with Moscow.
While Ukraine is not a NATO member, there will be some relief in the West and the Kremlin that it appeared to be the source of the accidental strike, rather than Russia, as Ukraine is an ally of the West and won’t face the military retaliation that Russia would.
What does Article 5 mean and was it triggered by the missile strike in Poland?
Article 5 of the NATO treaty says that in the event of an “armed attack” on a member state, the other members will take action they “deem necessary” including “the use of armed force”.
But it’s up to the member states to decide whether a given incident constitutes an armed attack or not. And in this case, as NATO believes the missile reached Poland accidentally and was fired by an ally (Ukraine), there’s no reason to think that this would trigger Article 5.
What is Article 4 and was it invoked by Poland or other NATO members?
Article 4 of the NATO treaty says “the Parties [member nations] will consult together whenever, in the opinion of any of them, the territorial integrity, political independence or security of any of the Parties is threatened.”
Leaders of NATO member states held an impromptu meeting alongside the G20 summit in Indonesia within hours of the missile landing in Poland. This led some commentators to suggest that Poland or another member state had already invoked Article 4.
But on Wednesday lunchtime, the Polish prime minister said the country was still considering whether to trigger Article 4, adding that it may not be necessary.