Pope Francis urges world leaders to protect environment, weakest and the poorest

Pontiff maps out his priorities as leader of the world's 1.2 billion Roman Catholics.

VATICAN CITY // Pope Francis urged princes, presidents, sheikhs and thousands of ordinary people gathered for his installation Mass yesterday to protect the environment, the weakest and the poorest, mapping out a clear focus of his priorities as leader of the world's 1.2 billion Roman Catholics.

The Argentine native is the first pope from Latin America and the first named for the 13th-century friar St Francis of Assisi, whose life's work was to care for nature, the poor and most disadvantaged. Echoing the gentleness for which St Francis is known, the pope said a little bit of tenderness can "open up a horizon of hope."

The Vatican said between 150,000-200,000 people attended the Mass, held under bright blue skies after days of chilly rain and featuring flag-waving fans from around the world. In Buenos Aires, thousands of people packed the central Plaza di Mayo square to watch the celebration on giant TV screens and erupted in joy when Pope Francis called them from Rome, his words broadcast to the crowd over loudspeakers.

"I want to ask a favour," Pope Francis told them. "I want to ask you to walk together, and take care of one another. ... And don't forget that this bishop who is far away loves you very much. Pray for me."

Back in Rome, the pope was interrupted by applause several times during his homily, including when he spoke of the need to protect the environment, serve one another with love and not allow "omens of destruction," hatred, envy and pride to "defile our lives."

Pope Francis said the role of the pope is to open his arms and protect all of humanity, but "especially the poorest, the weakest, the least important, those whom Matthew lists in the final judgment on love: the hungry, the thirsty, the stranger, the naked, the sick and those in prison."

Pope Francis, 76, thrilled the crowd at the start of the Mass by taking a long roundabout through the sun-drenched piazza and getting out of his jeep to bless a disabled man. It was a gesture from a man whose short papacy so far is becoming defined by such spontaneous forays into the crowd and concern for the disadvantaged.

The blue and white flags from Argentina fluttered above the crowd, which Italian media initially estimated could reach 1 million. Civil protection crews closed the main streets leading to the square to traffic and set up barricades for nearly a two kilometres along the route to try to control the masses and allow official delegations through.

Before the Mass began, Francis received the fisherman's ring symbolising the papacy and a woollen stole symbolising his role as shepherd of his flock. He also received vows of obedience from a half-dozen cardinals - a potent symbol given his predecessor Benedict XVI is still alive and was reportedly watching the proceedings on TV from the papal retreat in Castel Gandolfo.

About 132 official delegations attended, including more than a half-dozen heads of state from Latin America, a sign of the significance of the election for the region.