"May God repay all those, both individuals and states, who generously work to provide assistance and welcome to the numerous migrants and refugees," Francis said after a year that saw more than one million migrants reach Europe.
He called for "encouragement... to all those fleeing extreme poverty or war, travelling all too often in inhumane conditions and not infrequently at the risk of their lives."
Francis praised those who are helping migrants "to build a dignified future for themselves and for their dear ones, and to be integrated in the societies which receive them."Pope Francis offered a Christmas message today of mitigated hope for an end to the world's conflicts, backing recent accords on Syria and Libya and praising those who shelter migrants.
"We pray... that the agreement reached in the United Nations may succeed in halting as quickly as possible the clash of arms in Syria," he said, while urging that "the agreement on Libya be supported by all."
Delivering his Christmas message from the balcony of St Peter's Basilica, the 79-year-old pontiff touched on several other conflict zones, including Iraq, Yemen, the DR Congo, Burundi and South Sudan following a year of violence and suffering that forced hundreds of thousands to flee their homes.
The pope, addressing tens of thousands of pilgrims in the sunny square, also decried "brutal acts of terrorism, particularly the recent massacres which took place in Egyptian airspace, in Beirut, Paris, Bamako and Tunis."
After a year that saw more than one million migrants reach Europe, Francis praised those who shelter them, asking God to "repay all those, both individuals and states, who generously work to provide assistance and welcome" to them.
The leader of the world's 1.2 billion Catholics also used the traditional "Urbi et Orbi" (to the city and the world) address to denounce the destruction of cultural heritage.
In a clear reference to the ISIS, he said their "atrocities... do not even spare the historical and cultural patrimony of entire peoples."
ISIS has launched a campaign of destruction against buildings and monuments that fall outside its harsh interpretation of Islam, ranging from Christian churches to Muslim graves, as well as ancient treasures like the temples of Palmyra.
Praying for the displaced to return
The plight of embattled Christians in the Middle East, especially where they have been threatened by the advance of ISIS, has been thrown into the spotlight this year, and in Iraq, the mood was sombre.
"We are praying for the restoration of peace and security and the return of the displaced to their land," said a worshipper at Our Lady of Salvation church in Baghdad, one member of a dwindling Christian community trickling in to churches.
She said 12 of her relatives lost their homes when IS took over Iraq's second city Mosul in 2014 and ordered Christians to convert to Islam, to pay a heavy tax as second-class citizens or face death.
In Bethlehem Thursday night, the head of the Roman Catholic Church in the Holy Land arrived for the traditional midnight mass at the Church of the Nativity -- built over the site where Christians believe Jesus was born.
Travelling from Jerusalem nearby, the Jordanian Latin patriarch Fouad Twal would have had to pass through the Israeli wall that separates the two cities, with Bethlehem located in the occupied West Bank.
A wave of violence has led to a sharp decline in pilgrims visiting Bethlehem and the rest of the Holy Land this year, and only a sparse crowd was on hand to welcome Twal's procession.
In many countries across the world, Christians were fearful for their future, and some were even prohibited from celebrating the holy day.
'Beijing's 'white Christmas'
Queen Elizabeth II of Britain was to deliver her Christmas address later today in which she will focus on the string of terrorist attacks that blighted 2015, according to excerpts released by Buckingham Palace.
"It is true that the world has had to confront moments of darkness this year, but... 'the light shines in the darkness, and the darkness has not overcome it,'" she will say, quoting the Gospel of John.
A total of 130 people were killed in the November 13 attacks in Paris, while this year has also seen a string of mass casualty attacks in countries including Nigeria, Syria and Iraq.
Meanwhile weather around the world did not always cooperate with the "white Christmas" narrative, as East coast Americans shed their sweaters to enjoy soaring temperatures, while further south deadly tornadoes cut a swathe through rural communities.
But Beijing residents woke up to a white Christmas of sorts -- the sky was obscured by thick toxic smog rather than snow after more than 100 million people across China had been warned to stay indoors.
Meanwhile the Twitterverse enjoyed the offbeat story of Tim Peake, the first British astronaut on the International Space Station, dialling a wrong number when trying to phone home for Christmas, asking a woman "Is this planet Earth?"
"I'd like to apologise to the lady I just called by mistake saying 'Hello, is this planet Earth?' - not a prank call...just a wrong number!" he tweeted late on Thursday.
Get Breaking news, live coverage, and Latest News from India and around the world on NDTV.com. Catch all the Live TV action on NDTV 24x7 and NDTV India. Like us on Facebook or follow us on Twitter and Instagram for latest news and live news updates.