WATCH: Pentagon addresses report that Russian missiles killed 2 in Poland

Russia pounded Ukraine’s energy facilities Tuesday with its biggest barrage of missiles yet, striking targets across the country and causing widespread blackouts, and a U.S. official said missiles crossed into NATO member Poland, where two people were killed.

Watch the briefing in the player above.

Polish government spokesman Piotr Mueller did not immediately confirm the information from a senior U.S. intelligence official, who spoke on condition of anonymity because of the sensitive nature of the situation. But Mueller said top leaders were holding an emergency meeting due to a “crisis situation.”

Polish media reported that two people died Tuesday afternoon after a projectile struck an area where grain was drying in Przewodów, a Polish village near the border with Ukraine.

Pentagon Spokesman Brig. Gen. Pat Ryder said the Defense Department is aware of the press reports, but he said the Pentagon has not corroborated the reporting.

Neighboring Moldova was also affected. It reported massive power outages after the strikes knocked out a key power line that supplies the small nation, an official said.

READ MORE: Russian air strikes cause widespread blackouts in Ukraine, cross into NATO-member Poland

Ukrainian President Volodymir Zelenskyy said Russia fired at least 85 missiles, “most of them at our energy infrastructure,” and shut down power in many cities.

His energy minister said the attack was “the most massive” bombardment of power facilities in the nearly 9-month-old Russian invasion, striking both power generation and transmission systems.

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.

The power grid was already battered by previous attacks that destroyed an estimated 40 percent of the country’s energy infrastructure.

Russian President Vladimir Putin has not commented on the retreat from Kherson since his troops pulled out in the face of a Ukrainian offensive. But the stunning scale of Tuesday’s strikes spoke volumes and hinted at anger in the Kremlin.

Correction: This headline incorrectly stated the Pentagon had confirmed an attack that killed two in Poland; the Pentagon has not corroborated those reports at this time.