The Council of Europe is leading the joint project to prepare the institutional, logistical and organisational foundations of the proposed tribunal, including the groundwork for the election of its judges and prosecutor.

The “advance team” will also support stakeholder engagements to bolster support for the special tribunal.

The European Union will contribute with €10 million to the Special Tribunal Advance Team (STAT) project through the European Commission’s Service for Foreign Policy Instruments.

The project will last for a maximum of 24 months, or until the work can be funded via the future Enlarged Partial Agreement on the Management Committee of the Special Tribunal.

Kaja Kallas, the EU’s foreign affairs chief, said: “Unpunished crimes only encourage future atrocities. The European Union’s release of the first €10 million to help set up a special tribunal for the crime of aggression against Ukraine is a concrete step towards justice.

“Russia’s leaders are responsible for this war, and they must be held accountable. There can be no impunity.”

Michael McGrath, the European commissioner for democracy, justice, the rule of law and consumer protection, added: “Our support for Ukraine is unwavering.

“The special tribunal is essential to ensuring a just and lasting peace by holding Russia accountable for its crime of aggression.

“There can be no durable peace without justice, and no justice without accountability. Today, we move one step closer to turning these principles into action.”

Council of Europe secretary-general Alain Berset said: “Today’s agreement is a major step towards ensuring justice and accountability for the people of Ukraine, without which there can be no lasting peace.

“The Council of Europe will determinedly work together with the European Union and other key partners around the world to uphold the values that we hold dear, to ensure respect for international law and to make sure that violence and impunity do not prevail.”