The sirens wailed again today In Kyiv, and the Fox News team heard explosions nearby. 

Russian missiles were launched in a massive attack against Ukraine Tuesday, and one struck inside Poland, igniting big international concerns.

Early reports said a Russian missile landed three miles inside Poland, striking an agricultural site, killing two people perhaps by accident  

Ukrainian President Zelenskyy was still very concerned. 

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Polish explosion

A vehicle travels past a police blockade after an explosion in Przewodów, a village in eastern Poland near the border with Ukraine, Nov. 16, 2022.  (REUTERS/Kacper Pempel)

"This is a very significant escalation. We must act," he said in a TV address. 

It's significant because any attack on a NATO country by another nation could trigger "Article 5" military action by the alliance. NATO says it’s concerned but is not confirming the reports. Neither is the Pentagon. 

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"We don’t have any information at this time to corroborate those reports," Pentagon spokesman Gen. Pat Ryder said, "and we are looking into this further."

Moscow is flatly denying it was involved. According to a defense ministry spokesman, "No strikes were made against targets near the Ukrainian-Polish state border by Russian means of destruction."

Kyiv under attack

Firefighters work to put out a fire in a residential building hit by a Russian strike amid Russia's attack on Ukraine, in Kyiv, Ukraine Nov. 15, 2022. (REUTERS/Gleb Garanich)

Later reports suggested what landed in Poland might have been fragments of a Russian missile shot down by Ukrainian air defenses.

Poland is confirming the missile was Russian made.   

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A Fox News crew saw something similar when it went to the scene of a Russian strike in Kyiv Tuesday. A Russian missile flying over Kyiv had been hit by a Ukrainian missile and fell in pieces to the ground, badly damaging and setting fire to an apartment building. One person was killed, another was injured. 

When Fox reached the neighborhood, the fire was out, but the damage was evident. Emergency workers swarmed over the scene. Some carted away shards of the missile. 

Polish government meet following missile attack

Polish government spokesman Piotr Muller speaks to the media after a meeting in Warsaw of the security committee about the missile attack on the territory of Poland Nov. 15, 2022.   (Maciek Jazwiecki/Agencja Wyborcza.pl via REUTERS )

One eyewitness told Fox the fireball in the sky was "shocking." Another said it was simply the work of the "Russian terror state."

All told, according to officials here, some 90 Russian missiles were launched across the country, and 70 were shot down by Ukraine. Fifteen hit the power grid, leaving millions nationwide without electricity. 

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NATO says it will consider acting on the cross-border missile incident. Poland reportedly suggested the alliance’s "Article 4" be considered, which is a response to a threat rather than an attack by another nation on an alliance member.