Regardless of who fired the missile that killed two people in eastern Poland, it is Russia who "bears ultimate responsibility" for the incident, U.S. Secretary of Defense Lloyd Austin charged Wednesday.
Austin said the "tragic and troubling incident is yet another reminder of the recklessness of Russia's war of choice."
"Ukraine has a bedrock right to defend itself, and we will continue to stand in solidarity with the people of Ukraine as they defend their country," he told reporters at the Pentagon alongside Joint Chiefs Chairman Mark Milley.
The missile in question landed late Tuesday in the village of Przewodow, which lies near the border with Ukraine.
The incident sparked fears of an escalation between NATO, of which Poland is a member, and Russia.
But NATO Secretary-General Jens Stoltenberg said initial analysis suggested it was "likely caused by a Ukrainian air defense missile fired to defend Ukrainian territory," an analysis backed up by Poland.
The strike came as Ukraine attempted to fend off an unprecedented wave of Russian missile attacks that targeted key energy infrastructure vital to Ukraine's civilian population as winter approaches.
Milley, the top uniformed U.S. military official, said Russia launched as many as 100 missiles Tuesday in what was "likely" the largest volley of missile strikes since the Kremlin began its war against Ukraine in February. About one-quarter of Ukraine's civilian population is now without power, he said.
Russia is "imposing a campaign of terror, a campaign of maximum suffering, on the Ukrainian civilian population in order to defeat Ukrainian morale," said Milley. "The deliberate targeting of the civilian power grid, causing excessive collateral damage, and unnecessary suffering on the civilian population, is a war crime."
Austin said pivotal air defense systems known as NASAMS are now operational in Ukraine and were 100% effective in intercepting Russian missiles Tuesday.
"We're also working to secure more critical equipment to protect and repair Ukraine's energy infrastructure after Russia's indefensible attacks," he added.
Still, Milley acknowledged the possibility of Ukraine being able to secure a military victory "anytime soon" against Russia is "not high," but said the potential for a political resolution that leads to a full Russian withdrawal "is possible."
The U.S. also said Wednesday it has not seen anything that will contradict an assessment by Poland about the missile explosion in the eastern part of that country.
"We have seen nothing that contradicts President Duda's preliminary assessment that this explosion was most likely the result of a Ukrainian air defense missile that unfortunately landed in Poland," National Security Council spokesperson Adrienne Watson said in a statement.
"We have full confidence in the Polish government's investigation of the explosion near their border with Ukraine, and we commend them for the professional and deliberate manner in which they are conducting it," it added.
Watson said U.S. authorities will not get ahead of their Polish counterparts' work and remain in close touch with them "as we are still gathering information."
"We will continue to assess and share any new information transparently as it becomes available," she said.
But according to the US, it is Russia to blame for the missile landing in Poland.
"That said, whatever the final conclusions may be, it is clear that the party ultimately responsible for this tragic incident is Russia, which launched a barrage of missiles on Ukraine specifically intended to target civilian infrastructure.
"Ukraine had — and has — every right to defend itself," said the statement.
