The Vatican's permanent observer to the United Nations told a committee of the world body that "civilian populations continue to be victims of widespread and systematic attacks."
Where there is "credible evidence" of such attacks, "there must be accountability," he said.
"Crimes against humanity are among the most serious crimes under international law and their prevention and punishment concerns the entire international community," Archbishop Gabriele Caccia said Oct. 11.
He made the remarks in a statement he delivered to the U.N. General Assembly's Sixth Committee during its plenary meeting on crimes against humanity.
Attacks against civilian populations "are a reality of our times," but they are "clearly prohibited under customary international law," the archbishop said, adding that "the perpetrators of these heinous crimes continue to enjoy impunity."
"Although crimes against humanity are conceptually distinct from war crimes, we must acknowledge that civilians are particularly at risk wherever war rages," he said, deploring "massacres, torture, rape and the deliberate, indiscriminate targeting of civilian areas and humanitarian corridors."
He drew particular attention to the issue of human trafficking.
Enslavement and the subsequent human trafficking are one of the darkest and most revolting realities in the world today," he said. "Millions of men, women and children are enslaved, sold and trafficked as part of a systemic attack on civilians."
"Crimes against humanity affect us all," Archbishop Caccia continued, stressing the need for stronger international cooperation to prevent these attacks.
The "primary responsibility for protecting civilian populations from such crimes lies with member states" of the U.N., he said. "However, some domestic legal systems lack either laws to prosecute such crimes or the capacity to investigate them.
"In addition, crimes against humanity frequently have effects beyond the borders in which they occur since they may destabilize peace and security."
Archbishop Caccia called for "a global convention on crimes against humanity," which he said would indeed further strengthen the current framework of international humanitarian law, international criminal law and human rights law."
To that end, he said, the Holy See's delegation to the U.N. supports further discussions on the draft articles on "The Prevention and Punishment of Crimes Against Humanity" adopted by the International Law Commission at its 71st session in 2019.
But any such convention "must focus squarely on codifying existing customary law and promoting international cooperation," the archbishop said.
It also should build upon the principle of "aut dedere aut judicare" (Latin for "either extradite or prosecute"), he said.
This principle is the legal obligation of nation states under public international law to prosecute persons who commit serious international crimes where no other country has requested extradition. It sets out the duty of these states to prosecute crimes against humanity within their borders.
The international community has a responsibility to protect populations from crimes against humanity, Archbishop Caccia reiterated, noting that such a convention, adopted by consensus, would advance that aim.