A senior US intelligence official reported that several Russian-made missiles flew over Poland, a NATO country, and killed two people.

A spokesman for the Polish government said that top leaders held an emergency meeting to discuss the situation.

The incident prompted G-7 and NATO leaders to hold an emergency meeting to deliberate on the issue noting that a deliberate attack on any NATO member could cause a collective military response by member countries.

Polish media reported that the projectiles had killed two people and hit a village near the Ukraine-Poland border known as Przewodow, where the villagers had put their grain to dry.

The Russian government released a statement denying their involvement in the Poland strike. The Defense Ministry said that the country did not strike any targets near the Polish border, adding that Russian weapons did not cause damage caused by the strike.

US officials said initial assessments suggested that Ukrainian forces had fired the missile against an incoming Russian missile when Russia launched an attack on Ukraine’s electric power plant on Tuesday.

Responding to suggestions by Ukraine’s President Zelenskyy that Russia had deliberately launched the missiles on Poland, the Pentagon said it was also looking into the reports. Brig. Gen. Pat Ryder, press secretary for the US Defense Department, told reporters that the government was aware of the reports but had no information corroborating them.

The Polish Foreign Ministry gave a statement identifying the weapon as old and Russian-made. However, Polish President Andrzej Duda said that even though the missile was made in Russia, its origins and who fired it were still unverified.

President Biden, attending the G20 summit in Indonesia, was awakened overnight by the news of the missile strike. He expressed the country’s full support for the Polish investigation on Twitter and reaffirmed the US commitment to NATO.

Over the morning, more intelligence information came in from satellite-based systems, and it became clear to US officials examining the intel and speaking to Polish officials that the missile appeared to have been launched by Ukraine in defense.

The Polish government said it would raise its military preparedness levels even though it was still investigating the incident.

President Biden has said that the US would support Poland or any other NATO member against Russia.

In March, President Biden told Russia not to think about attacking even an inch of NATO territory. He said the country was obligated under Article 5 to defend all NATO members.

He warned President Vladimir Putin again in September as he was speaking from the White House, saying that the US was fully prepared to defend its NATO allies and every inch of NATO territory.

Poland’s and NATO’s statements about the incident suggest that they do not consider it a deliberate attack on Poland, as a statement from NATO called it a tragic incident.

The strike occurred during Russia’s biggest coordinated attack on Ukrainian energy facilities, striking important infrastructures and leaving Ukraine in darkness.