Pope Francis's peace envoy Thursday met with a Russian official wanted by the ICC over allegations of illegally transferring Ukrainian children to Russia and Moscow's spiritual leader Patriarch Kirill.
Cardinal Matteo Zuppi began his visit to Russia earlier this week, in a first such trip since President Vladimir Putin sent troops to Ukraine in February 2022.
"Met with Cardinal Matteo Zuppi," Moscow's ombudswoman for children's rights Maria Lvova-Belova said in a statement.
"We discussed humanitarian issues related to military operations and the protection of children's rights.
"I am sure that Christian love and mercy will help in dialogue and mutual understanding," she added.
The International Criminal Court, which is based in The Hague, released arrest warrants for Lvova-Belova as well as Putin in March.
The court said the orders were linked to the war crime accusation of unlawfully deporting Ukrainian children.
Kyiv says more than 16,000 Ukrainian children have been deported to Russia since the beginning of the Kremlin's large-scale military campaign in Ukraine and that many were placed in institutions and foster homes.
The Kremlin and Lvova-Belova have dismissed the allegations and pointed out that Russia does not recognise the jurisdiction of the court.
Zuppi visited Kyiv earlier this month.
At the time, Ukrainian President Volodymyr Zelensky appealed to the Italian cardinal to help secure the release of Ukrainian prisoners of war and the return the children he says were "deported" to Russia.
Zuppi also met with the leader of the Russian Orthodox church, Patriarch Kirill, in a rare meeting for a high-ranking Catholic official.
The Russian church leader is a staunch supporter of Putin and the offensive in Ukraine, often portraying the conflict in religious terms.
"I am very happy that you have come to Moscow," Patriarch Kirill told Zuppi in Moscow's Danilov monastery.
"At a time when relations between Russia and the West are going through serious problems ... it is very important that all the forces that want to preserve peace and justice unite," he said, pointing to the threat of a "major world war".
He urged the two churches to join hands to prevent the situation from "taking a negative turn".
Relations between the Vatican and the Russian Orthodox Church remain strained after a schism in the churches almost 1,000 years ago.
Zuppi delivered a mass at Moscow's main Catholic cathedral later Thursday. He is due to return to the Vatican on Friday.