Preparations for the establishment of a special tribunal to address the crime of aggression against Ukraine have been completed, according to an announcement by Alain Berset, Secretary General of the Council of Europe.
The tribunal is intended to prosecute the political and military leadership of the Russian Federation for launching the full-scale invasion of Ukraine in 2022.
The development marks a significant procedural step by the so-called Core Group of states, which has been working since 2023 on mechanisms to enable legal accountability for the crime of aggression.
The group held its latest meeting in Strasbourg from 19 to 21 March 2025, during which it concluded its work on three key legal and technical documents that will serve as the foundation for the tribunal.
These documents include:
- A draft bilateral agreement between Ukraine and the Council of Europe on the establishment of the special tribunal.
- A draft statute outlining the structure, jurisdiction, and operational framework of the tribunal.
- A draft enlarged partial agreement to define the management and participation of member states in supporting the tribunal’s operations.
The finalised texts will now be submitted for political consideration by the participating states of the Core Group. Berset welcomed the outcome of the meeting, noting the readiness of the Council of Europe to support the tribunal’s rapid launch, subject to political approval.
“I welcome the successful conclusion of the Core Group meeting and the completion of the necessary technical and legal documentation for the establishment of the special tribunal within the framework of the Council of Europe,” Berset stated. He further called on member states to “demonstrate the political will necessary to ensure the tribunal’s creation.”
The proposed tribunal is being developed specifically to address the crime of aggression, defined under international law as the planning, preparation, initiation or execution of an act of using armed force by a state against the sovereignty, territorial integrity or political independence of another state. Unlike war crimes or crimes against humanity, which fall under the jurisdiction of the International Criminal Court (ICC), the ICC currently lacks a mandate to prosecute crimes of aggression involving non-State Parties to the Rome Statute. Neither Ukraine nor Russia are full State Parties.
Discussions on the creation of a tribunal to prosecute Russian officials for aggression began in 2022 but initially made limited headway. While there has been widespread political support for legal accountability among Ukraine’s partners, practical measures to establish a functioning legal body were slow to materialise.
A breakthrough occurred in February 2025 during the 13th session of the Core Group, where a consensus was reportedly reached to proceed with the establishment of the tribunal based on a bilateral agreement between Ukraine and the Council of Europe. The decision avoided the need for a multilateral treaty or reliance on the United Nations Security Council, where Russia holds veto power.
The Core Group consists of more than 40 participating states, including EU members, the United Kingdom, the United States, Canada, Japan and others. Although the United States is not a member of the Council of Europe, it has expressed support for the initiative. According to Council of Europe officials, there have been no negative signals from Washington regarding the tribunal’s creation under the organisation’s auspices.
The final structure of the tribunal is expected to involve an international panel of judges and prosecutors, operating under a legal framework derived from international law, but rooted in the bilateral arrangement between Ukraine and the Council of Europe. It will not be a fully independent international court in the traditional sense, but rather a hybrid mechanism, with political and legal backing from a coalition of supportive states.
In practical terms, once the political endorsement from member states is secured, the tribunal could be operationalised within months. However, the timeline remains contingent on the speed with which the states adopt the necessary agreements and nominate personnel.
The proposed tribunal will have jurisdiction only over the crime of aggression and is not expected to overlap with ongoing investigations by the ICC into war crimes and crimes against humanity committed during the war in Ukraine.
Further details on the initiative are expected to be made public following internal consultations within the Council of Europe and among Core Group members. Berset has reiterated the organisation’s readiness to provide the institutional platform necessary to host the tribunal and has expressed confidence in the legal framework developed by the Core Group.
In an earlier interview, Berset noted that the tribunal was on course to be established within 2025, and added that no opposition had been registered from the administration of US President Donald Trump, suggesting broad international consensus on the matter.
The establishment of the special tribunal would mark the first international legal mechanism focused exclusively on prosecuting the crime of aggression since the Nuremberg and Tokyo trials following the Second World War.
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