Pope Francis will on Sunday return to the island of Lesbos, the migration flashpoint he first visited in 2016, to plead for better treatment of refugees as attitudes towards migrants harden across Europe.

On the second day of a landmark trip to Greece, Francis will visit the temporary camp of Mavrovouni, where nearly 2,200 asylum seekers currently live.

At the start of his visit on Saturday, Francis said Europe was 'torn by nationalist egoism'
At the start of his visit on Saturday, Francis said Europe was 'torn by nationalist egoism' AFP / Louisa GOULIAMAKI

The pope's trip to Lesbos will be shorter than his last, officials said, as he will fly back to Athens on Sunday to hold a mass for some 2,500 people at the Megaron Athens Concert Hall.

On Lesbos, the pontiff will deliver an Angelus prayer in a camp tent in the presence of Greek President Katerina Sakellaropoulou, EU vice-president Margaritis Schinas and Greek Migration Minister Notis Mitarachi.

"His visit is a blessing," said Rosette Leo, a Congolese asylum seeker carrying a two-month-old baby as she waited in line for the ceremony.

On Lesbos, the pontiff will deliver an Angelus prayer in a camp tent
On Lesbos, the pontiff will deliver an Angelus prayer in a camp tent AFP / ARIS MESSINIS

"He has power, he can influence people to see refugees differently," she told AFP.

Officials have not ruled out the possibility that some migrants from Mavrovouni could accompany him back to Italy
Officials have not ruled out the possibility that some migrants from Mavrovouni could accompany him back to Italy POOL via AFP / COSTAS BALTAS

Francis has long championed refugees, whom he called the "protagonists of a terrible modern Odyssey" in a speech to Greek officials and Schinas on Saturday.

He was speaking in Athens during the first papal visit in 20 years.

Ahead of the Lesbos visit, 31-year-old Cameroonian camp resident Christian Tango said he hoped the pope would "carry the voice (of refugees) to the whole world".

NGOs and aid groups have raised concerns about the new camps, arguing that people's movements should not be restricted
NGOs and aid groups have raised concerns about the new camps, arguing that people's movements should not be restricted AFP / Louisa GOULIAMAKI

As with other residents, Tango is only allowed to leave the camp once a week. But on Sunday, he will get to speak to the pope.

The Mavrovouni tent camp was hurriedly erected after the sprawling camp of Moria, Europe's largest such site at the time, burned down last year.

NGOs and aid groups have raised concerns about the new camps, arguing that people's movements should not be restricted
NGOs and aid groups have raised concerns about the new camps, arguing that people's movements should not be restricted AFP / Louisa GOULIAMAKI

Greek authorities blamed a group of young Afghans for the incident and security has been substantially enhanced ahead of the pontiff's visit with 850 police officers deployed.

In Cyprus, where the pope visited before Greece this week, authorities said that 50 migrants will be relocated to Italy thanks to Francis.

Greek officials have not ruled out the possibility that some migrants from Mavrovouni could accompany him back to Italy.

Migrants at the the temporary camp of Mavrovouni on the Greek island of Lesbos
Migrants at the the temporary camp of Mavrovouni on the Greek island of Lesbos AFP / Louisa GOULIAMAKI

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 Europe was "torn by nationalist egoism" instead of acting as an "engine of solidarity" on migration.

"Today, and not only in Europe, we are witnessing a retreat from democracy," he said, warning against populism's "easy answers".

In 2016, Francis visited Moria with Bartholomew I, the spiritual leader of the world's Orthodox Christians, and Archbishop Ieronymos II, head of the Church of Greece.

In a ceremony later held at the port of Mytilene, the three leaders held mass to bless the thousands who had died trying to reach Europe.

The Mavrovouni camp currently holds 2,193 people and has a capacity of 8,000, the facility's deputy chief Dimitris Vafeas told ERT state TV this week.

"Everyone is staying in containers in good conditions. Asylum procedures are significantly improved, no one spends more than three to four months in the camp -- except exceptional cases," he said.

With EU funds, Greece is building a series of "closed" facilities on Greek islands with barbed wire fencing, surveillance cameras, X-ray scanners and magnetic gates that are closed at night.

Three such camps have opened on the islands of Samos, Leros and Kos, with Lesbos and Chios to follow next year.

NGOs and aid groups have raised concerns about the new camps, arguing that people's movements should not be restricted.

Greece vehemently denies the claims, insisting its coastguard saves lives at sea.

The pope will return to Rome on Monday.