European leaders on Wednesday hailed a new "register of damage" for Ukraine they signed on to as "historic" and a first step to making Russia pay for its war.
The instrument, created by the 46-nation Council of Europe, sets up an evidentiary record ahead of a possible future prosecution of Russian leaders, thus laying the groundwork for compensation.
It was a "first, necessary, urgent step" ensuring "justice that is centred on the victims" of the war, said council head Marija Pejcinovic Buric on arrival at the second day of the summit in Iceland.
She said that by early Wednesday 40 countries had signed onto the creation of the register, including the United States and all other G7 nations.
Another three countries were finalising internal procedures to do so.
She and other leaders emphasised that countries outside the Council of Europe -- a pan-continental rights body separate from the European Union but incorporating all 27 EU member states -- could back the register.
"There will be no reliable peace without justice," President Volodymyr Zelensky said in a video address at the summit opening on Tuesday.
Ukraine, a Council of Europe member, strongly welcomed the initiative.
Russia was kicked out of the council last year after invading Ukraine.
Several EU countries are in favour of Ukraine's demand that a special court be set up to try Russia's leadership for war crimes.
The Hague-based International Criminal Court in March issued an arrest warrant for Putin, accusing him of unlawfully deporting Ukrainian children.
The register of damage, also to be lodged in The Hague, with a satellite office in Ukraine, will detail war-time claims of harm and destruction wrought by Russia.
Initially established for three years, "It paves the way towards a future international comprehensive compensation mechanism for the victims of the Russian aggression," a Council of Europe statement said.
- Ukraine presses for jets -
"It's important to give a message to people who have damages that we will not forget them, and that we will follow up afterwards," Belgian Prime Minister Alexander De Croo said.
The move by the wider European community highlighted Russia's isolation on the continent.
It also came just after Zelensky wrapped up a whirlwind tour of major European capitals that saw Germany, France and Britain all vow to step up arms deliveries to Ukraine.
Ukraine is believed to be preparing an offensive on Russian positions in the east of its territory to be launched within weeks.
Zelensky is intent on boosting air defences as Russia deploys missiles and drones to inflict long-range damage.
He is pressing Western allies to provide advanced fighter jets but they are wary, fearing it could escalate the war.
British Prime Minister Rishi Sunak and Dutch counterpart Mark Rutte agreed on the first day of the summit that they would build an "international coalition to provide Ukraine with combat air capabilities, supporting with everything from training to procuring F-16 jets".