A senior adviser to Ukrainian President Volodymyr Zelenskiy said on Wednesday that Russia was to blame for any “incidents with missiles” after waging war on his country.

Mykhailo Podolyak made his comments in a written statement after U.S. President Joe Biden said a missile that killed two people in Poland was probably not fired from Russia.

“In my opinion, it is necessary to adhere to only one logic. The war was started and is being waged by Russia. Russia massively attacks Ukraine with cruise missiles. Russia has turned the eastern part of the European continent into an unpredictable battlefield,” Podolyak said.

“Intent, means of execution, risks, escalation – all this is only Russia. And there can be no other explanation for any incidents with missiles.”

The two deaths were at a Polish grain facility near the Ukrainian border on Tuesday as Russia carried out missile strikes across Ukraine.

Podolyak said that “when an aggressor country launches a deliberate massive missile attack on the entire territory of a large country on the European continent with its outdated Soviet weapons (class X missiles), a tragedy sooner or later also occurs on the territories of other states.”

“Moreover, Russian missiles or their fragments have fallen more than once in border zones. I don’t see the slightest sense in departing from this simple logic – only Russia is guilty of threats and excesses in other countries with its missile attacks,” he said.

Podolyak said separately on Twitter that it was time for Europe to “close the sky” over Ukraine, adding: “No need to look for excuses and postpone key decisions.”