Pope Francis on Sunday returned to the island of Lesbos, the migration flashpoint he first visited in 2016, calling the neglect of migrants the "shipwreck of civilization."
The pope has long championed the cause of migrants and his visit comes a day after he delivered a stinging rebuke to Europe which he said was "torn by nationalist egoism."
"In Europe, there are those who persist in treating the problem as a matter that does not concern them," the pope said as he spent some two hours at Lesbos' Mavrovouni camp where nearly 2,200 asylum seekers live.
On the second day of his visit to Greece, he met dozens of child asylum seekers and relatives standing behind metal barriers and stopped to embrace a boy called Mustafa.
"I am trying to help you," Francis told one group through his interpreter.
People later gathered in a tent to sing songs and psalms to the pontiff.
Pope Francis warned that the Mediterranean "is becoming a grim cemetery without tombstones" and that "after all this time, we see that little in the world has changed with regard to the issue of migration."
He said the root causes "should be confronted – not the poor people who pay the consequences and are even used for political propaganda."
The European Union has been locked in a dispute with Belarus over an influx of migrants travelling through the former Soviet state seeking to enter Poland, Lithuania, and Latvia in recent months.
Britain and France have also traded barbs over the increasing number of migrants making the deadly Channel crossing to reach the UK in the wake of the November 24 mass drowning which claimed 27 lives.
"His visit is a blessing," said Rosette Leo, a Congolese asylum seeker at the site.
However, Menal Albilal, a Syrian mother with a two-month-old baby whose asylum claim was rejected after two years on the island, said refugees "want more than words, we need help."
"The conditions here are not good for a baby," she told AFP.
"The Greek government should think about us, we've been here for two years without work or education," said François Woumfo, from Cameroon.
The temporary Mavrovouni tent camp was hurriedly erected after the sprawling camp of Moria, Europe's largest such site at the time, burned down last year.
Greek authorities blamed a group of young Afghans for the incident and security was substantially enhanced for the pontiff's Sunday visit.
The pope's trip to Lesbos was shorter than his last as he will hold a mass for some 2,500 people at the Megaron Athens Concert Hall later in the day.
In Cyprus, where the pope visited before Greece this week, authorities said that 50 migrants will be relocated to Italy thanks to Francis.
He took 12 Syrian refugees with him during his last visit to Lesbos in 2016.
At the start of his Athens visit on Saturday, Francis said that "today, and not only in Europe, we are witnessing a retreat from democracy," warning against populism's "easy answers."