The International Criminal Court was sending war crimes investigators to Ukraine in what it called the largest such deployment in its history.
"This represents the largest-ever single field deployment by my office since its establishment," Karim Khan, the ICC chief prosecutor, said.
The 42-member team — which comprises investigators, forensic experts, and support staff — "will significantly enhance the impact of our forensic and investigative actions on the ground," Khan added.
Shortly after the war in Ukraine began in February, Khan announced he was opening an investigation into possible war crimes committed during the conflict.
The team would ensure that "evidence is collected in a manner that strengthens its admissibility in future proceedings'' at the court based in the administrative capital of the Netherlands.
They would chase up leads and collect witness testimony "relevant to military attacks." They would also work with Ukrainian authorities to "strengthen the chain of custody with respect to hard evidence."