Pope Benedict called in his Easter message on Sunday for an end to injustice, hatred and violence around the world, including in Tibet, Iraq and Darfur.

The pope, who turns 81 next month, celebrated an Easter Mass for tens of thousands of people in driving rain in St Peter's Square as Christians around the world commemorated Christ's resurrection.

The Sunday mass came hours after an Easter vigil service on Saturday night where, in a surprise move, the pope baptised Muslim-born convert Magdi Allam, 55, an outspoken journalist and fierce critic of Islamic extremism.

The wind and rain that has whipped most of Europe did not spare Rome as the German pontiff, wearing white and gold vestments, said Mass while the crowd huddled under umbrellas.

The pope himself was sheltered by a canopy but cardinals, diplomats and altar boys were drenched and thunderclaps punctuated the service.

In his twice-yearly "Urbi et Orbi" (to the city and the world) message delivered after the Mass, the pope decried "the many wounds that continue to disfigure humanity in our own day".

"These are the scourges of humanity, open and festering in every corner of the planet, although they are often ignored and sometimes deliberately concealed; wounds that torture the souls and bodies of countless of our brothers and sisters," he said.

He called for "an active commitment to justice ... in areas bloodied by conflict and wherever the dignity of the human person continues to be scorned and trampled".

"It is hoped that these are precisely the places where gestures of moderation and forgiveness will increase!," he said, specifically mentioning Darfur, Somalia, the Holy Land, Iraq, Lebanon and Tibet.

He then wished the world a happy Easter in 63 languages.

It was his second appeal in less than a week for calm in Tibet. In both cases he did not mention China, with which the Vatican has tense relations.

The Egyptian-born Allam's conversion to Christianity -- he took the name "Christian" for his baptism -- was kept secret until the Vatican disclosed it in a statement less than an hour before the Saturday night service began.

Allam, who is a strong supporter of Israel, is under police protection following threats against him.

"For the Catholic Church, each person who asks to receive baptism after a deep personal search, a fully free choice and adequate preparation, has a right to receive it," the statement said.

Allam defended the pope in 2006 when the pontiff made a speech in Regensburg, Germany, that many Muslims perceived as depicting Islam as a violent faith.

The Vatican statement announcing Allam was joining Catholicism said all newcomers were "equally important before God's love and welcome in the community of the Church".

At Sunday morning's mass the pope read a prayer saying that after Christ's resurrection some 2,000 years ago "thousands and thousands ... converted to the Christian faith" and he added: "This is a miracle that still renews itself today".

Allam, who has been living in Italy for 35 years, has said he was never a very devout Muslim. Still, his conversion to Christianity came as a surprise.

"What amazes me is the high profile the Vatican has given this conversion," Yaha Sergio Yahe Pallavicini, vice-president of the Italian Islamic Religious Community, said. -Reuters