VATICAN CITY - Pope Leo XIV set the tone for his papacy with a call to stop exploiting nature and marginalising the poor at his inaugural mass on Sunday.
It was attended by dignitaries, including Ukraine's Volodymyr Zelensky and US Vice President JD Vance.
Ten days after he became the first US head of the world's 1.4 billion Catholics, some 200,000 people gathered to see his inaugural mass in St Peter's Square, according to the Vatican.
Before it started, the Chicago-born Robert Francis Prevost delighted the crowds by taking to the popemobile for the first time, smiling, waving and blessing those he passed.
In his homily, the soft-spoken 69-year-old returned to the themes of peace, reconciliation and social justice that have marked his first few days as pope.
"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," he said.
In a prayer afterwards, he noted the ongoing efforts to end the war in Ukraine, before holding a private audience with Zelensky and his wife.
"The martyred Ukraine is waiting for negotiations for a just and lasting peace to finally happen," Leo said.
Succeeding the charismatic but impulsive Francis, Leo took over a Church still battling the fallout of the clerical child abuse scandal, and trying to adapt to the modern world.
He acknowledged on Sunday some trepidation in his new role.
"I was chosen, without any merit of my own, and now, with fear and trembling, I come to you as a brother who desires to be the servant of your faith and your joy," he said.
In his homily he warned against "closing ourselves off in our small groups".
At the mass, Leo received the pontifical emblems -- the pallium, a strip of cloth worn around the neck, and the fisherman's ring, which is forged anew for each pope.
He will wear the ring on his finger until he dies, when it will be destroyed.