Pope Francis compared Russia’s war in Ukraine to the famine of the 1930s, which killed millions of Ukrainians and was engineered by Soviet dictator Joseph Stalin.
The square in Vatican City is named Francis Square.
The famine of 1932 and 1933 was designed by Stalin to consolidate his power over Ukraine as he worried about a possible soviet union break-up.
Many people argue that it was genocide.
The famine killed up to 28,000 Ukrainians a day, with most historians listing the death toll at around 3.8 million people.
There are allegations of war crimes in the ongoing war in Ukraine.
Russian forces have committed war crimes, including torture and rape, as well as being accused of weaponizing global hunger by intermittently blocking Ukrainian grain exports, according to the United Nations.
Russia’s invasion of Ukraine has been condemned repeatedly by Francis.
He called on Putin to stop this spiral of violence and death after Russia illegally annexed four regions of Ukraine.
The Pope urged the assembly to pray for the victims of the genocide and for the babies who are dying.