Pope Francis has made an Easter Sunday peace plea, saying conflicts have lasted too long in Syria, and between the Israelis and Palestinians.
The former Cardinal Jorge Bergoglio of Argentina, who has made defence of nature an early hallmark of his pontificate, also condemned the "iniquitous exploitation of natural resources" and urged everyone to be "guardians" of creation.
Francis delivered his message from the central balcony of St Peter's Basilica - the same spot from where he first appeared to the world as pope after his election on 13 March - to a crowd estimated by the Vatican at at least 250,000 people.
"Peace in Asia, above all on the Korean peninsula: may disagreements be overcome and a renewed spirit of reconciliation grow," he said, speaking in Italian.
North Korea said it was entering a "state of war" with South Korea.
Tensions have been high since the North's new young leader Kim Jong-un ordered a third nuclear weapons test in February, breaching UN sanctions and ignoring warnings from North Korea's sole major ally, China, not to do so.
Francis, who has brought a more simple and personal style to the papacy, said the message of Easter is that faith can help people transform their lives by letting "those desert places in our hearts bloom".
"How many deserts, even today, do human beings need to cross! Above all, the desert within, when we have no love for God or neighbour, when we fail to realise that we are guardians of all that the creator has given us and continues to give us," he said.
Earlier, at a Mass in a square bedecked by more than 40,000 plants and flowers, the pope wore relatively simple white vestments, as opposed to his predecessor Benedict, who preferred more elaborate robes.
The huge crowd spilled out of St Peter's Square and into surrounding streets and included many who had come to see a pope they hope could give a new start to a Church that has been marred by scandals involving sexual abuse of children and allegations of corruption.
"It's a new pope and new beginning," said Tina Hughes, 67, who came to Rome with her family from Nottingham, England to see the pope. "I think he brings something special. He connects with people. I feel good about him."
Francis, who took his name in honour of St. Francis of Assisi, who is revered as a symbol of austerity and the importance of the natural world, said:
"Peace in the whole world, still divided by greed looking for easy gain, wounded by the selfishness which threatens human life and the family, selfishness that continues in human trafficking, the most extensive form of slavery in this 21st century.
"Peace to the whole world, torn apart by violence linked to drug trafficking and by the iniquitous exploitation of natural resources! Peace to this our Earth! May the risen Jesus bring comfort to the victims of natural disasters and make us responsible guardians of creation."
Easter Sunday, the day Christians believe Jesus was resurrected from the dead three days after his crucifixion, was the culmination of four hectic days of activity for the pope, during which he instituted several novelties.
On Holy Thursday, two women were included among the 12 people whose feet he washed and kissed during a traditional ceremony that had previously been open only to men.
Francis is still living in the same Vatican guesthouse where he stayed during the conclave that elected him the first non-European pope in 1,300 years, instead of moving into the regal papal apartments in the Vatican's Apostolic Palace.
He has also been inviting ordinary people to his morning Mass at the guesthouse, including Vatican street sweepers and gardeners.