Several countries and organisations, including the UN, pledged on Wednesday to bring to justice any perpetrators of war crimes committed during Russia's invasion of Ukraine.
They were urged on by the Lebanese-British barrister Amal Clooney, who said she feared "politicians calling for justice but not delivering it."
"My fear is that you will get busy and distracted and that each day there'll be a little bit less coverage of the war and people will become a little bit more numb to it," Clooney told an informal meeting of the Security Council.
"And that Ukraine will end up alone in pursuing the perpetrators of these atrocities. We cannot let that happen," said the lawyer, who runs the Clooney Foundation for Justice with her husband, actor George Clooney.
Albanian Foreign Minister Olta Xhacka said that the "perpetrators of these crimes must and will be held accountable."
Michelle Bachelet, the UN High Commissioner for Human Rights, insisted that victims and their families "need to obtain effective remedies for the harm and tragedy they have endured."
She said that to date her office had "documented and verified 5,939 civilian casualties, with 2,787 killed and 3,152 injured."
"Actual figures are considerably higher, and my office is working to estimate them," she added, pointing out that most of the dead and injured were victims of "the use of explosive weapons with wide area effects in populated areas, such as shelling from heavy artillery, and missile and air strikes."
Ukraine's prosecutor general, Iryna Venediktova, said via video link that she had opened more than 8,000 investigations into alleged violations of war-related humanitarian law.
The prosecutor of the International Criminal Court (ICC), Karim Khan, said a record 43 countries had referred the situation in Ukraine to his organisation.
"The law applies equally to all sides. All parties to the conflict, whether Ukraine or the Russian Federation, whether they're state actors or non-state actors, have certain clear obligations," he said, promising to conduct "independent investigations."
Russia, for its part, accused Ukraine of committing abuses and said it considers the ICC to be biased.
