Pope Francis called for freedom of thought and tolerance in his Easter Sunday address, as the weakened pontiff delighted the crowds of Catholic faithful by making a much hoped-for holiday appearance, even circling St. Peter's Square in his popemobile.

"Happy Easter," said the 88-year-old Argentine pope in a weak voice from his wheelchair on the balcony of St. Peter's Basilica, to the great joy of the crowd in the flower-filled square below. 

The pope's convalescence from pneumonia has kept him away from most Holy Week events, but Francis made a major effort on Sunday, waving at the crowd and blessing babies from his popemobile for nearly 15 minutes despite appearing listless. 

After giving his Easter greetings to the crowd, estimated at more than 35,000 people, from the basilica's balcony, Francis delegated the reading of his traditional "Urbi et Orbi" ("To the City and the World") benediction to an associate.

"There can be no peace without freedom of religion, freedom of thought, freedom of expression and respect for the views of others," read his speech, which also condemned "worrisome" anti-Semitism, and the "dramatic and deplorable" situation in Gaza. 

With his health still delicate following five weeks in hospital for pneumonia in both lungs, it had not been certain whether the leader of the world's 1.4 billion Catholics would be present, or if so, in what capacity.

Among the believers on Sunday was fellow Argentine Maria Repezza, 58, who was holding back tears. 

"I'm moved by the strength he puts out, because he is sick and very old. He is an Argentine like us, he's ours. We feel blessed," she told AFP.

'Not targets but people'

Just ahead of the pope's appearance at St. Peter's, he held a brief private meeting with US Vice President JD Vance, who was visiting Rome with his family.

Vance did not stay for the Easter mass and after just a quarter of an hour he left the Vatican and headed with his wife and children to attend mass at the Basilica of Saint Paul Outside the Walls, one of the four Vatican-owned papal basilicas in Rome.

Video footage showed Francis in his wheelchair shaking hands with the vice president and his wife, with the Vatican writing later in a brief statement that the meeting "gave the opportunity to exchange greetings on Easter Sunday."

Their encounter came months after a spat between Francis and the administration of US President Donald Trump over its anti-migrant policies.

The pope's Easter message was one of tolerance towards others and respect for diversity — themes he has hammered throughout his 12-year papacy.

But they are especially topical given the myriad conflicts around the globe, most of which were mentioned by the pontiff, including Sudan, Yemen and Ukraine. 

"On this day, I would like all of us to hope anew and to revive our trust in others, including those who are different than ourselves, or who come from distant lands, bringing unfamiliar customs, ways of life and ideas!" read the speech.

He appealed to the world's leaders "not to yield to the logic of fear which only leads to isolation from others." 

Citing "defenceless civilians" and attacks on "schools, hospitals and humanitarian workers", the pope said "we cannot allow ourselves to forget that it is not targets that are struck, but persons, each possessed of a soul and human dignity."

While citing a "growing climate of anti-Semitism" around the world as "worrying," the pope said his thoughts were with the people of Gaza and repeated his calls for a ceasefire in the Israel-Hamas war. 

"The terrible conflict continues to cause death and destruction and to create a dramatic and deplorable humanitarian situation," he wrote in the address. 

Improving, but still weak  

Francis was released from hospital on 23 March, after five weeks of treatment for pneumonia, from which he nearly died.

Despite improvements in his breathing, his voice remains weak, although in recent appearances, including on Sunday, he has not worn a nasal cannula through which he has been receiving oxygen.

For the first time since becoming pope in 2013, Francis missed most Holy Week events, such as Friday's Stations of the Cross at the Colosseum and Saturday's Easter vigil at Saint Peter's Basilica, where he delegated his duties to cardinals.

He did, however, make a brief appearance inside the basilica on Saturday, where he prayed and gave candies to children.

Some 300 cardinals, bishops and priests attended Sunday's Easter mass, while the crowd was larger than usual, organisers said, due to the Jubilee, a holy year designated by the pope that attracts thousands of pilgrims to the Eternal City. 

In his one official engagement this week, Francis visited inmates in a Rome jail, after which he told a journalist he was getting through the Easter week "as best I can."

This year's Easter is unusual as it falls on the same weekend in both the Catholic and Protestant branches of Christianity, which follow the Gregorian calendar, and the Orthodox branch, which uses the Julian calendar.