A Hague-based international prosecutorial team launched efforts Monday to prepare case materials against Russia for the crime of aggression — a crime that is notoriously difficult to prosecute on the international stage.

The International Center for the Prosecution of the Crime of Aggression (ICPA) was established within Eurojust, the European Union’s agency for judicial cooperation, according to statements released by the organization.

The office will draw together prosecutors from various European countries, as well as from the International Criminal Court (ICC), to gather evidence of Russian aggression in Ukraine. “The war in Ukraine is the most documented in history, and, for the first time, active investigations into the crime of aggression are taking place while an armed conflict is still ongoing. At the same time, we are dealing with an international crime that has rarely been prosecuted and for which there is no standard practice.”

The center will gather evidence with the awareness that it remains unclear where the crime of aggression will ultimately be prosecuted — be it in national courts, a dedicated international tribunal, or within the ICC.

The initiative was initially announced by EU President Ursula von der Leyen in February 2023, who said at the time that “Russia must be held accountable in courts for its odious crime.”

David M. Crane, who was the founding chief prosecutor of the UN Special Court of Sierra Leone, and now runs the Global Accountability Network, told JURIST the ICPA’s launch was “an important initiative that shows Western democracies are starting to come to grips together on dealing with Russian aggression.” He added: “It’s not a solution but the beginning of a beginning. There is still a need for an international Special Tribunal for Ukraine on the Crime of Aggression.”