Two Polish citizens were killed by a Russian-made missile on Tuesday, raising fears that Russia’s war in Ukraine could spill over into NATO territory.

KYIV, Ukraine — Poland said early Wednesday that a Russian-made missile fell in the eastern part of the country, killing two people in a blast that Ukrainian President Volodymr Zelenskyy decried as “a very significant escalation” of the war.
The exact circumstances of the fatal explosion were unclear, including who fired the missile and from where. The Polish government said it was investigating and raising its level of military preparedness. NATO planned to hold an emergency meeting to discuss the events close to the Ukrainian border. Russia denied any involvement.
Zelenskyy’s comments, delivered in an evening address to the nation, came hours after a senior U.S. intelligence official told The Associated Press that Russian missiles had crossed into Polish territory and killed two people.
A second person said that apparent Russian missiles struck a site in Poland about 15 miles from the Ukrainian border.
A statement from the Polish Foreign Ministry identified the weapon as being made in Russia. President Andrzej Duda was more cautious, saying that it was “most probably” Russian-made but that its origins were still being verified.
“We are acting with calm,” Duda said. “This is a difficult situation.”
Elsewhere, President Joe Biden convened an emergency meeting of the Group of Seven and NATO leaders in Indonesia for consultations on the situation in Poland.

Biden, who was awakened overnight by staff with the news of the missile while attending the Group of 20 summit, called Polish President Andrzej Duda to express his condolences. On Twitter, Biden promised “full U.S support for and assistance with Poland’s investigation,” and “reaffirmed the United States’ ironclad commitment to NATO.”
Meanwhile, NATO Secretary-General Jens Stoltenberg called the meeting of the alliance’s envoys in Brussels. The U.N. Security Council also planned to meet Wednesday for a previously scheduled briefing on the situation in Ukraine. The strike in Poland was certain to be raised.
Poland’s statement did not address whether the strike could have been a targeting error or if the missile could have been knocked off course by Ukrainian defenses.
In their statements, Poland and NATO used language that suggested they were not treating the missile blast as an intentional Russian attack, at least for now. 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.
Polish media reported that the strike took place in an area where grain was drying in Przewodów, a village near the border with Ukraine.
The Russian Defense 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.
Polish Foreign Minister Zbigniew Rau summoned the Russian ambassador and “demanded immediate detailed explanations,” the government said.
The strike came to light Tuesday as Russia pounded Ukraine’s energy facilities with its biggest barrage of missiles yet, striking targets across the country and causing widespread blackouts.
The barrage also affected neighboring Moldova. It reported massive power outages after the strikes knocked out a key power line that supplies the small nation, an official said.
The missile strikes plunged much of Ukraine into darkness and drew defiance from Zelenskyy, who shook his fist and declared: “We will survive everything.”
In his nightly address, the Ukrainian leader said the strike in Poland offered proof that “terror is not limited by our state borders.”
“We need to put the terrorist in its place. The longer Russia feels impunity, the more threats there will be for everyone within the reach of Russian missiles,” Zelenskyy said.
Russia fired at least 85 missiles, most of them aimed at the country’s power facilities, and blacked out many cities, he said.
The Ukrainian energy minister said the attack was “the most massive” bombardment of power facilities in the nearly 9-month-old invasion, striking both power generation and transmission systems.
The minister, Herman Haluschenko, accused Russia of “trying to cause maximum damage to our energy system on the eve of winter.”
The aerial assault, which resulted in at least one death in a residential building in the capital, Kyiv, followed days of euphoria in Ukraine sparked by one of its biggest military successes — the retaking last week of the southern city of Kherson.
Poland considers invoking NATO Article 4
Poland is a member of the North Atlantic Treaty Organization (NATO). Polish officials said Warsaw is considering invoking NATO Article 4 in order to discuss its concerns with the security alliance’s decision-making body, and will also increase the combat readiness of some Polish troops.
“We decided to increase the combat readiness of selected units of the Polish armed forces, with particular emphasis on airspace monitoring,” Polish Prime Minister Mateusz Morawiecki said in a Tuesday address, explaining that “airspace monitoring is and will be carried out in an enhanced manner together with our allies.”
Morawiecki stressed that evidence suggests the missile that landed was a “single act” and there is no evidence of further missiles.
The North Atlantic Treaty Organization is a group of 30 North American and European nations. According to NATO, its purpose “is to guarantee the freedom and security of its members through political and military means.”
The alliance was created in 1949 in response to the start of the Cold War. Its original purpose was to protect the West from the threat posed by the Soviet Union. Since the end of the Cold War, many former Soviet nations have joined NATO, much to the annoyance of Putin.
Article 4, which Poland is considering, is a consultation method that allows members to bring an issue, usually a security issue, affecting them for discussion at the North Atlantic Council, the alliance’s decision making body.
“The Parties 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,” the article states.
The best-known aspect of the alliance is Article 5 of the treaty, which, if invoked, means “an attack against one Ally is considered as an attack against all Allies.” It has only ever been invoked once, in response to the September 11, 2001 terrorist attacks on the United States