Poland's Foreign Ministry says Russian-made missile fell near its border with Ukraine, killing 2

Update:NATO says there is no evidence that Russia launched an offensive attack on a NATO member.Read the latest here.

Poland's Foreign Ministrysaid early Wednesday that a Russian-made missile fell in the eastern part of the country near the Ukrainian border, killing two people. If verified, the blast would mark the first time in the war with Ukraine that Russian weapons came down on a NATO country.

Ukrainian President Volodymr Zelenskyy decried the explosion on Tuesday afternoon as "a very significant escalation" of the war.

Serious questions about the explosion remain, including who fired the missile. Russia denied any involvement.

The Polish government said it was investigating and raising its level of military preparedness. U.S. President Joe Biden pledged support for the investigation.

The Polish ministry said in a statement that Foreign Minister Zbigniew Rau summoned the Russian ambassador and "demanded immediate detailed explanations."

Polish government spokespersonPiotr Mueller said earlier some military units were put on alert while officials sought details.

Following the Foreign Ministry's statement, Polish PresidentAndrzej Dudastruck a more cautious tone when speaking with reporters.

"We do not have any conclusive evidence at the moment as to who launched this missile. It was most likely a Russian-made missile, but this is all still under investigation at the moment," he said.

Polish media reported that the blast was in an area where grain was drying in Przewodow, a village near the border with Ukraine.

The Russian Defence Ministry denied being behind "any strikes on targets near the Ukrainian-Polish border" and said in a statement that photos of purported damage "have nothing to do" with Russian weapons.

Itdescribedthe allegations as "a deliberate provocation aimed at escalating the situation."

NATO ambassadors to meet

Biden said it was "unlikely" that the missile was fired from Russia, but he convened an emergency meeting of the Group of Seven and NATO leaders who were in Indonesia for another summit. It was not immediately clear whether Biden was suggesting that the missile hadn't been fired by Russia at all.

Biden's decision to convene that meeting upended schedules for the final day of the Group of 20 meeting in Indonesia.

Three U.S. officials said preliminary assessments suggested the missile was fired by Ukrainian forces at an incoming Russian one. The officials spoke on condition of anonymity because they weren't authorized to discuss the matter publicly.

That assessment contradicted information earlier Tuesday from a senior U.S. intelligence official who told The Associated Press that Russian missiles crossed into Poland.

On Tuesday, Russia pounded Ukraine's energy facilities with its biggest barrage of missiles yet, striking targets across the country and causing widespread blackouts.

NATO Secretary General Jens Stoltenberghas called an emergency meeting for later Wednesday of the alliance's envoys to discuss the eventsin Poland.

Duda said that it was very likely that Poland would request consultations under Article 4 of the NATO military alliance.

According toArticle 4,members can raise any issue of concern, especially related to the security of a member country.

"Our ambassador will be attending the meeting of the North Atlantic Council tomorrow at 10 a.m. at NATO headquarters.... It is highly likely that the ambassador will request the activation of Article 4, or allied consultations," he said.

The UNSecurity Council also planned to meet Wednesday for a previously scheduled briefing on the situation in Ukraine. The events in Poland was certain to be raised.

In their statements, Poland and NATO used language that suggested they were not treating the missile blast as a Russian attack, at least for now.

Poland's statement did not address the circumstances of the strike, including whether it could have been a targeting error or if the missile could have been knocked off course by Ukrainian defences. A NATO statement called it a "tragic incident."

If Russia had deliberately targeted Poland, it would risk drawing the 30-nation alliance into the conflict at a time when it is already struggling to fend off Ukrainian forces.

Canada following situation 'very closely'

The incidentcould also raise questions about the useof NATO's Article 5, under which anattack on onealliance memberis consideredan attack against them all. It calls on the alliancemembers toassist the attacked countryby taking"such action as it deems necessary, including the use of armed force."

However, each country has no obligation to respond militarily.

Poland heldemergency talks with some of its NATO allies on Tuesdayafter theexplosion.

Foreign Affairs Minister MlanieJoly, who isattending a G20 summit in Indonesia, said Canada is "in contact with Poland as well as with our partners" as she expressed her condolences.

Asked by a reporter if Canada believes the situation triggers Article 5, she said, "We are following the situation very closely and of course we will be having important meetings today with allies."

WATCH | Assessing the fallout from Polish blast:

Russian missiles reportedly struck a Polish village. What happens next?

2 years ago

Duration 8:58

Roland Paris, former foreign policy adviser to Justin Trudeau, and former deputy NATO commander Andrew Leslie weigh in on the fallout from this incident.

Stoltenberg said in a statement he had spoken with Duda and that the alliance is monitoring the situation. He said it was "important that all facts are established."

The White House said Biden had offered Duda"deep condolences" for the loss of life, and full U.S. support with the investigation.

Ukraine decries 'Russian missile terror'

In Ukraine, Zelenskyywroteon Twitterthat he had a call with his Polish counterpart and "expressed condolences over the death of Polish citizens from Russian missile terror."

He had addressed the explosion in his nightly video address earlier, saying:"The longer Russia feels impunity, the more threats therewill be to anyone within reach of Russian missiles."

"To firemissiles at NATO territory! This is a Russian missile attack oncollective security! This is a very significant escalation. Wemust act,"he said.

Ukrainian Foreign Minister Dmytro Kulebaalso took to Twitter to denywhat he called a Russian "conspiracy theory" that it wasa Ukrainian air defence missile that struck Poland.