A deadly explosion took place Tuesday at a grain processing facility in Poland near the border with Ukraine, according to Polish media outlets, and top government officials later called an emergency meeting.
The cause of the explosion in the village of Przewodow, about four miles north of the Ukrainian border, was not immediately clear. A Polish radio station reported that two people were killed.
At a Pentagon briefing in Washington, Brig. Gen. Patrick S. Ryder said that the Defense Department was aware of media reports saying that two Russian missiles had landed in Poland, but said that U.S. defense officials had no corroborating information.
Poland’s prime minister, Mateusz Morawiecki, and president, Andrzej Duda, convened a meeting of the National Security Council in response to a “crisis situation,” a government spokesman, Piotr Mueller, told reporters. He asked reporters not to publish unconfirmed information, and said more information would be forthcoming.
Russia’s Defense Ministry denied any involvement in the explosion. On Telegram, the ministry wrote that any statements by Polish officials or media outlets about Russian missiles hitting the village were a “deliberate provocation.”
“No strikes on targets near the Ukrainian-Polish state border were made,” the ministry wrote.
Russia launched a widespread missile attack on Ukraine on Tuesday, with roughly 100 missiles that were aimed primarily at the country’s electrical infrastructure. Ukraine’s Volyn region, where Russian rocket strikes were reported on Tuesday, lies across the border from Przewodow.
That raised the possibility of the explosion being linked to an errant missile, or the remains of one that had been targeted by Ukraine’s air defense systems.
The Ukrainian air force said the defense systems had shot down 70 of more than 90 incoming missiles on Tuesday. A fragment of one destroyed missile struck a residential building in Kyiv, killing one person.
Although the cause of the explosion remained unclear, Ukraine’s president, Volodymyr Zelensky, seized on reports of possible Russian involvement, calling it evidence of “a very significant escalation.”
Mr. Zelensky alluded to Poland’s membership in NATO and blamed Russia for what he called an “attack on collective security.”
Since the beginning of the invasion, Ukraine’s Western allies, including the United States, have sought to keep the fighting limited to Ukrainian territory and avoid direct confrontation between the alliance and Russia, even as they have supplied a steady stream of weapons to Kyiv.
A NATO official said the alliance was “looking into these reports and closely coordinating with our ally Poland.”
Vedant Patel, a U.S. State Department spokesman, said the United States was working with the Polish government and other members of NATO to gather more information.
Asked whether it would matter if any damage was found to be accidental or intentional, he said, “Of course that is something that would be important.”
Steven Erlanger, Julian E. Barnes, Richard Pérez-Peña Monika Pronczuk, Michael Crowley and Carly Olson contributed reporting.