Law enforcement officials on Monday open an international center for the prosecution of the crime of aggression, the first step toward building cases against individuals behind Russia's 2022 invasion of Ukraine.
Ukrainian authorities are reviewing more than 93,000 reports of war crimes and have indicted 207 suspects via domestic courts. High-level perpetrators are expected to be tried at the International Criminal Court (ICC) in The Hague.
The new International Centre for the Prosecution of the Crime of Aggression (ICPA), also in The Hague, will work alongside the ICC, the world's permanent war crimes court, and will fill a legal gap for that specific crime.
The ICC, which in March issued an arrest warrant for Russian President Vladimir Putin, has the jurisdiction to prosecute alleged war crimes, crimes against humanity and genocide in Ukraine, but due to legal constraints not the crime of aggression.
The new center will collect evidence for possible cases against Russian military and political leaders responsible for the war, Ukraine's top prosecutor, Andriy Kostin, said in an interview ahead of the opening.
"The aim is, of course, to build the case ... for future suspects in this tribunal," Kostin told Reuters. "We need experts, we need forensics, we need additional information, including intelligence information, in order for this case to be strong, because we all know that the crime of aggression is the leadership crime."
Annexing parts of eastern and southern Ukraine
President Vladimir Putin's government says it annexed parts of east and south Ukraine in a "special military operation" to "denazify" its neighbor, protect Russian speakers and defend its borders from aggressive Western ambitions.
Kyiv and its Western allies accuse Putin of barbaric tactics and an imperialist-style land grab in Ukraine. Russia denies targeting civilians or committing war crimes.
Ukraine wants aggression crimes to be heard at a special tribunal, an idea supported by most European Union countries, the United States and Britain, among others. It is still unclear under what legal basis that court will be created.
Kostin said the center was a sign of international support for a special tribunal "and we believe that this center will bring us (the) first results in coming months."
Despite operating during an ongoing conflict, Ukraine's war crimes unit has charged 347 suspects and convicted 53 individuals, Kostin said.
It is expected to target around two dozen top government and military officials, according to legal experts.