A blast in NATO member Poland, near the Ukraine border, on Tuesday sent shockwaves across the world, with fears of a direct confrontation between the alliance and Russia.
After the incident, Polish President Andrzej Duda said the explosive, which killed two people in the eastern village of Przewodow, was “most likely Russian-made”.
But on Wednesday, he said it was “very likely” that the missiles were from Ukraine’s air defence.
“Absolutely nothing indicates that this was an intentional attack on Poland,” he said. “It’s very likely that it was a rocket used in anti-missile defence, meaning that it was used by Ukraine’s defence forces.”
Washington and NATO have made similar statements, suggesting the blast was unintentional.
Russia immediately denied its missiles struck Poland while Ukraine was quick to blame Moscow.
Here’s what you need to know.
What do we know about the explosion?
First news of the incident was reported by Polish Radio ZET, which said on Tuesday that two missiles had hit Przewodow, a village in eastern Poland about six kilometres (3.5 miles) from the border with Ukraine, killing two men.
Residents of the village, with a population in the hundreds, told local media that a missile had hit a grain drying facility, near a school.
The Polish foreign ministry later said a weapon fell on Przewodow at 3:40pm (14:40 GMT).
President Duda said “it was most likely a Russian-made missile” but noted Warsaw had no conclusive evidence on who fired it and that the incident was still under investigation.
He also described the incident as “a one-off event” and said there was “no indication” it would be repeated.
A day later, he said there was no evidence the blast was an intentional attack, and, in line with NATO, claimed the missile was likely part of Ukraine’s defensive air systems.
What was happening in Ukraine at the time?
The explosion in Poland came on a day of sustained Russian shelling in Ukraine.
Moscow’s forces launched 110 missiles and 10 Iranian-made attack drones throughout the country, the general staff of Ukraine’s armed forces said, leaving millions of households without power.
Ukraine said more than 70 missiles were shot down, but some hit the city of Lviv, near the border with Poland to the west.
Al Jazeera’s Jonah Hull, reporting from Kyiv, said it had been a “hugely kinetic” day.
“The explosion in Poland … only added to a sense of crisis,” Hull said.
The turmoil started “receding” on Wednesday, as information suggested the blast was the result of a Ukrainian attempt to down a Russian missile.
“NATO member after NATO member is now standing back and urging caution and saying they are awaiting the outcome of an investigation [into the incident],” Hull said.
How did Ukraine and Russia react?
Ukraine was quick to blame Russia for the missile blast.
President Volodymyr Zelenskyy said on Tuesday, without producing evidence, that Russian missiles hit Poland in a “significant escalation” of the conflict.
“The longer Russia feels impunity, the more threats there will be to anyone within reach of Russian missiles. To fire missiles at NATO territory. This is a Russian missile attack on collective security. This is a very significant escalation. We must act,” Zelenskyy said in his nightly video address.
Russia said the explosion was caused by a Ukrainian air defence missile.
“The photos published in the evening of November 15 in Poland of the wreckage found in the village of Przewodow are unequivocally identified by Russian defence industry specialists as elements of an anti-aircraft guided missile of the S-300 air defence system of the Ukrainian air force,” the Russian defence ministry said in a statement on Wednesday.
The ministry also said that Russian attacks in Ukraine on Tuesday had been 35km (22 miles) from the Polish border at their nearest point to the NATO member state.
Kremlin spokesman Dmitry Peskov accused a number of countries of having made “baseless statements” about Russia’s involvement “without having any idea of what had happened”.
In rare praise for Washington, he lauded its “measured” response after United States President Joe Biden said it was “unlikely” the missile had come from Russia.
As fears of an escalation eased, Ukraine said it wants access to the site of the explosion and to see the information that provided the basis for its allies’ conclusions.
What have the US and NATO said?
The US and its NATO were cautious in their early responses.
Asked whether it was too early to say that any missile was fired from Russia, Biden said that the trajectory suggested otherwise.
“There is preliminary information that contests that,” he told reporters at the G20 summit in Indonesia. “I don’t want to say that until we completely investigate it but it is unlikely … that it was fired from Russia, but we’ll see.”
NATO Secretary-General Jens Stoltenberg said the alliance’s member states were “monitoring” the situation and “closely consulting” with one another.
“[It is] Important that all facts are established,” he tweeted on Tuesday.
On Wednesday, NATO said the blast was most likely the result of a Ukrainian accident but ultimately blamed Russia as the aggressor force.
Spoke with President Duda @prezydentpl about the explosion in #Poland. I offered my condolences for the loss of life. #NATO is monitoring the situation and Allies are closely consulting. Important that all facts are established.
— Jens Stoltenberg (@jensstoltenberg) November 15, 2022
Was the incident talked about at the G20?
Al Jazeera’s Rob McBride, reporting from the G20 summit in Indonesia, said the explosion in Poland was “very much overshadowing” the last day of the meeting – Wednesday – which is being attended by Sergey Lavrov, Russia’s foreign minister.
Western leaders convened an emergency roundtable in Bali after reports of the blast on Tuesday.
“I think the point that will be made by the US and its allies, even if it is determined to have been a Ukrainian missile, is that it was fired as a direct result of Russia’s invasion of Ukraine,” McBride said.
What will happen next?
The explosion has sparked concern that NATO, which Poland joined in 1999, might be drawn into the conflict between Russia and Ukraine.
Poland, which has put its military on heightened alert following the blast, is protected by NATO’s commitment to collective defence enshrined in Article 5 of its founding treaty.
If it is determined that Moscow was to blame for the blast, which seems very unlikely following NATO’s statement on Wednesday, it could trigger Article 5, starting deliberations on a potential military response.
While the situation was less clear, Warsaw was expected to request urgent consultations under Article 4 of the NATO Treaty, which is invoked when any member state feels their “territorial integrity, political independence or security” are at risk.
Any response by the alliance will be heavily influenced by whether the incident was accidental or intentional – and for now, the former seems the most probable scenario.
Even so, Ukraine is still demanding more investigations.