Pope Leo XIV delivered a call to stop the exploitation and marginalisation of the poor, as well as highlighting his concerns about the war in Ukraine, at his inaugural mass on Sunday.
Ten days after he became the first US head of the world's 1.4 billion Catholics, about 200,000 people gathered to see his inaugural mass in St Peter's Square, according to the Vatican.
The mass was also attended by dignitaries including US Vice President JD Vance and Ukrainian President Volodymyr Zelenskyy.
“In this our time, we still see too much discord, too many wounds caused by hatred, violence, prejudice, the fear of difference, and an economic paradigm that exploits the Earth's resources and marginalises the poorest,” Pope Leo said.
In a prayer afterwards, he noted the continuing efforts to end the war in Ukraine, before holding a private audience with Mr Zelenskyy and his wife.
“The martyred Ukraine is waiting for negotiations for a just and lasting peace to finally happen,” Pope Leo said.
Well-wishers waved US and Peruvian flags, with people from both countries claiming him as the first pope from their nations. Born in Chicago, the pontiff, 69, spent many years as a missionary in Peru and also has Peruvian citizenship.
Robert Prevost, a relative unknown on the world stage who only became a cardinal two years ago, was elected pope on May 8 after a short conclave of cardinals that lasted barely 24 hours.
He succeeded Francis, an Argentine, who died on April 21 after leading the Church for 12 often turbulent years during which he battled with traditionalists and championed the poor and marginalised.
The pontiff was pictured shaking hands with Mr Zelenskyy who also thanked the Vatican for “its readiness to become a platform for direct negotiations between Ukraine and Russia”.
Last week, Pope Leo offered the Vatican as a venue for potential peace talks after Russian President Vladimir Putin did not take up Mr Zelenskyy's offer to meet in Turkey.
Pope Leo did not meet the US vice president.
Mr Vance met the late Pope Francis the day before he died last month, and queued up to shake Pope Leo's hand on Sunday along with the other dignitaries.
Before becoming pope, Leo reposted on his personal X account criticism of US President Donald Trump's administration over its approach to migration.
But Mr Vance insisted on Sunday that the US was “very proud of him”.
Mr Vance did however meet Mr Zelenskyy for the first time since the chaotic meeting at the White House in February.
“We discussed the talks in Istanbul, where the Russians sent a low-level delegation with no decision-making powers,” Mr Zelensky wrote on Telegram following the meeting.
“We also touched on the need for sanctions against Russia, bilateral trade, defence co-operation, the situation on the battlefield and the future exchange of prisoners,” Mr Zelenskyy added.
US Secretary of State Marco Rubio and Mr Zelenskyy's aide Andriy Yermak were also present at the meeting, where the two sides discussed steps towards a just and lasting peace in Ukraine.
