With the cooperation of @blueboy1969 we analyzed the available photos of fragments and came to a clear conclusion that they belong to the 48D6 motor of the 5V55-series missile of the S-300 AD system- a Ukrainian one.

https://twitter.com/UAWeapons/status/1592629251161075712

UPDATE

Biden says “preliminary” information suggests it is “unlikely” missile that killed two in Poland was fired from Russia.

https://twitter.com/i/status/1592700234295119877