“Ukrainian government sources have owned up to the attack, but this claim of responsibility stopped short of being made publicly or officially: "A Ukrainian government official told The Washington Post that the country’s special services were behind the attack, though Kyiv stopped short of saying it was responsible — even as top officials taunted Moscow.”

https://www.zerohedge.com/geopolitical/large-explosion-destroys-part-key-bridge-linking-russia-crimea-zelensky-aide-says