Walentek’s death, who was an amateur MMA fighter, was announced on social media by MMA Poland, a sports organization with which he was associated.
State news agency PAP quotes his coach, Piotr Jeleniewski, as saying: “Few people knew what he had faced himself and what his difficult history as a soldier and wounded veteran was. He chose his path and left believing deeply in the legitimacy of his decision”.
Details about the circumstances of his death were not provided.
More than 20,000 foreigners are fighting on the Ukrainian side against Russia, media reported.