(CNN)A 96-year-old Holocaust survivor, Borys Romanchenko, was killed Friday by a Russian strike on the Ukrainian city of Kharkiv.
Romanchenko's death was confirmed by the Buchenwald concentration camp memorial institute in a series of tweets.
Romanchenko survived the camps at Buchenwald, Peenemünde, Dora and Bergen-Belsen during World War II, the memorial said, adding that it was "stunned" by news of his death.
It said Romanchenko worked "intensively on the memory of Nazi crimes and was vice-president of the Buchenwald-Dora International Committee."
The discovery of Buchenwald, on April 11, 1945, began the liberation of more than 21,000 prisoners from one of the largest Nazi concentration camps of World War II.
The official US military account of the liberation called the camp "a symbol of the chill-blooded cruelty of the German Nazi state," where thousands of political prisoners were starved and "others were burned, beaten, hung and shot to death."
Romanchenko's granddaughter told the memorial he was living in an apartment block in Kharkiv that was hit during a Russian attack.
In 2012, Romanchenko attended an event commemorating the liberation of Buchenwald, where he read an oath devoted to "creating a new world where peace and freedom reign," the memorial said.