Pope Francis on Tuesday called on countries to review their laws on migration in order to welcome refugees and help them integrate into society and become legal residents.
His appeal comes at a time when several countries in Europe want to shut their borders to migrants and refugees, while immigration is also a prominent issue in the U.S. presidential campaign.
"With regard to migrants, I would ask that legislation on migration be reviewed, so, while respecting reciprocal rights and responsibilities, it can reflect a readiness to welcome migrants and to facilitate their integration," he said in his message for the Roman Catholic Church's World Day of Peace.
The annual message is sent to heads of state and government as well as international organizations such as the United Nations.
"Special concern should be paid to the conditions for legal residency, since having to live clandestinely can lead to criminal behavior," he said.
During a planned visit to Mexico next February, the Latin American pope will say a Mass right on the border with the United States, where he is expected to defend the rights of immigrants.
U.S. politicians have debated for years over immigration, most recently about Latin Americans who entered the country illegally.
Conservative Republicans in the 2016 White House race are offering competing plans to limit illegal immigration. Republican presidential campaign front-runner Donald Trump has threatened to deport 11 million people.
Migrants, who were stranded between Greece and Macedonia, line up for a food distribution, outside the Tae Kwon Do stadium at the southern suburb of Faliro, in Athens, Greece, December 14, 2015. Photo: Reuters/Alkis Konstantinidis
Europe has seen hundreds of thousands of migrants and refugees reach its shores under precarious conditions this year and is deeply divided over how to deal with the crisis.
Several European Union member states have resisted a German-led proposal to set mandatory quotas that would oblige countries to take on a certain proportion of newly arrived migrants.
In September the pope appealed to every Catholic parish, religious community and sanctuary in Europe to take in a family of refugees. In his message on Tuesday, he thanked those he said had "readily responded," without giving any figures.
The 1.2 billion-member Church's World Day of Peace is marked by Catholics in parishes around the globe on Jan. 1. The theme of this year's message is "Overcome Indifference and Win Peace".
Francis, whose first trip after his election in 2013 was to the Sicilian island of Lampedusa to pay tribute to refugees who had died at sea, said many people had become cold hearted and indifferent to the tragedies facing humanity.
"Some people prefer not to ask questions or seek answers; they lead lives of comfort, deaf to the cry of those who suffer," he said.