STORY: Berlin's Pilecki Institute is collecting testimonies from refugees about possible war crimes in Ukraine.
Tapping into its experience researching 20th century history, including Nazi crimes in World War Two.
The Pilecki institute is named after a Polish cavalry officer who risked his life to document the situation in the Auschwitz concentration camp.
Mateusz Falkowski, the deputy head of the institute in Berlin, said researchers are creating an archive of oral history.
"I hope that Ukraine will not be forgotten. So, I am afraid. I'm afraid that after some weeks, months, years, the people in the West will just forget. And the hope is that they will not forget - that is, that they will remember. And they in that case they will be able to rely on these interviews, on these materials, on these documents."
The International Criminal Court started a formal investigation into possible war crimes and crimes against humanity in Ukraine after Russia invaded two months ago.
More than 369,000 people fleeing the war have been registered in Germany, Interior Ministry data showed on Friday.
The witness interviews start by asking for a short written description of the witness's own situation during the war and then follow up with specific questions, created with the help of lawyers.
"So there are the questions, for example, about what happened on a specific day in this place, so in Mariupol or in Kherson or other places where they were? And what exactly did they see and when? And whether it's about, for example, the destruction of civilian infrastructure, whether it's about the destruction of monuments or perhaps churches, or about sexual violence or other aspects of violence during the war."
On Friday, the U.N.'s human rights office said there was growing evidence of Russian war crimes in Ukraine, including signs of indiscriminate shelling and summary executions, and said Ukraine also appeared to have used weapons with indiscriminate effects.
Russia describes its incursion as a "special military operation" to disarm and "denazify" Ukraine. It denies targeting civilians or committing war crimes.