Taoiseach Leo Varadkar has signed a declaration that pledges to bring the perpetrators of aggression in Ukraine to justice.
The Register of Damages caused by Russia in Ukraine, 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.
European countries are now actively working to gather evidence of all Russia's actions in Ukraine with aim of ensuring there are financial reparations in the future.
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 this morning 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.
The Greek Prime Minister Katerina Sakellaropoulou summed up the mood of the meeting saying "without justice there can be no peace".
While Iceland emphasised the need for more international assistance to be provided to the victims of gender-based violence in Ukraine.
The Reykjavik Declaration which affirms Europe's values of peace and democracy has also got the backing of the US, Canada and Japan.
Read more: Ireland pledges €325,000 in extra funding to Council of Europe
Last night, Mr Varadkar met the President of the European Court of Human Rights, Síofra O'Leary, an Irish judge.
He will also hold a bilateral meeting with Icelandic Prime Minister Katrín Jakobsdóttir.
The meeting will examine how Ireland and Iceland can cooperate on oceans, biodiversity, wind and wave energy, and climate change.
The discussions are likely to touch on the work of the Galway Marine Institute and also the network of arctic researchers of Ireland.
The Taoiseach will also attend two sessions on maintaining European unity on Ukraine.
'No reliable peace without justice' - Zelensky
There are also moves afoot to establish a way to deliver justice for the crimes committed.
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.
"There will be no reliable peace without justice," President Volodymyr Zelensky said in a video address at the summit opening yesterday.
Ukraine, a Council of Europe member, strongly welcomed the initiative.
Russia was kicked out of the council last year after invading Ukraine.
Mr Varadkar said that work in also underway to boost support for Ukraine among African and Latin American countries.
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 Mr 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.
Mr 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".
Additional reporting AFP
