WASHINGTON (NEXSTAR) -- On Wednesday, Defense Secretary Lloyd Austin said a rocket explosion in Poland Tuesday was not an escalation of the war in Ukraine. 

"This explosion was most likely the result of a Ukrainian air defense missile that unfortunately landed in Poland," Austin said.

Initially, the missile that killed two people in a rural area of Poland appeared to be from Russia, but now the Polish President said there is no evidence it was part of an intentional attack.

"Our information supports what President Duda said earlier in his preliminary assessment," Austin said.

However, Ukrainian President Volodymyr Zelensky is rejecting the idea the missile was part of Ukrainian defenses. The State Department says, for now, they will stand by the Polish reports.

"We're going to continue to convey information to our Ukrainian partners as the facts on the ground and more information comes to light," State Department Spokesperson Vedant Patel said.

While that investigation continues, the U.S. and its allies were quick to remind the world that no matter where the missile originated, Ukraine is not at fault. 

"The world knows that Russia bears ultimate responsibility for this incident," Austin said.

"This whole incident is caused by Russia's brutal war in Ukraine," NATO Secretary General Jens Stoltenberg said.

U.S. officials said this incident will not impact ongoing efforts to support Ukraine in this war.