Pope Francis appeared to ask Russians to seek the truth about their country's invasion of Ukraine in his Easter message to the world on Sunday and appealed for dialogue between Israelis and Palestinians following recent violence.

Francis, 86, presided at a solemn Easter day Mass in a sunny St. Peter's Square after unseasonal cold forced him to skip an outdoor service on Friday - a precaution following his hospitalisation for bronchitis at the end of March.

A carpet of 38,000 flowers donated by the Netherlands bedecked the square for the most important and joyous date in the Church's liturgical calendar - commemorating the day Christians believe Jesus rose from the dead. Honour units of Vatican Swiss Guards and Italian Carabinieri police - both in ceremonial dress - stood at attention.

But the traditional pomp and sacred singing then gave way to modern realities. Francis later went up to the central balcony of St. Peter's Basilica to deliver his twice-yearly "Urbi et Orbi" (to the city and the world) message and blessing, addressing a crowd the Vatican estimated at about 100,000.

There, from the same spot where he first appeared to the world as pope on the night of his election in 2013, he spoke of "the darkness and the gloom in which, all too often, our world finds itself enveloped", and prayed to God for peace.

"Help the beloved Ukrainian people on their journey towards peace, and shed the light of Easter upon the people of Russia," he said.

Since Russia invaded Ukraine in February last year, Francis has at least twice a week referred to Ukraine and its people as being "martyred" and has used words such as aggression and atrocities to describe Russia's actions.

On Sunday he asked God to "comfort the wounded and all those who have lost loved ones because of the war, and grant that prisoners may return safe and sound to their families. Open the hearts of the entire international community to strive to end this war and all conflict and bloodshed in our world."

Ukrainian President Volodymyr Zelenskiy, in his nightly video address, denounced Russian attacks that coincided with the observance of Orthodox Palm Sunday, including an attack that killed a father and daughter in the city of Zaporizhzhia.

"This is how the terrorist state marks Palm Sunday," Zelenskiy said. "This is how Russia places itself in even greater isolation from the world."

The majority of Ukraine's 41 million people are Orthodox Christians who celebrate Easter a week from now.

As he has done every Easter, Francis called for peace in the Middle East, his appeal made more urgent by recent violence in Jerusalem and cross-border exchanges of fire involving Israel, Lebanon and Syria.

"On this day, Lord, we entrust to you the city of Jerusalem, the first witness of your resurrection. I express deep worry over the attacks of these last few days that threaten the hoped-for climate of trust and reciprocal respect, needed to resume the dialogue between Israelis and Palestinians, so that peace may reign in the Holy City and in the entire region," he said.

MIDDLE EAST TENSIONS

Israeli-Palestinian tensions have sharply increased since Israeli police raids last week on Al-Aqsa mosque in Jerusalem, which caused outrage across the Arab world.

Between the Mass and his reading of the message, Francis, appearing in fine form, was driven in a popemobile around the square and down the main boulevard leading to the River Tiber so more people could see him.

In his message, Francis also mentioned instability in Lebanon, expressed the hope that the "martyred Rohingya people" of Myanmar "may encounter justice", and called for more aid for the victims of earthquakes in February that killed nearly 56,000 people in Turkey and Syria.

In a section of the address where he mentioned Nicaragua, the pope asked God to "remember all who are prevented from freely and publicly professing their faith".

Relations between the government and Catholic Church in Nicaragua are deeply strained. The government, which has suspended diplomatic relations with the Vatican, banned outdoor Holy Week processions this year.