Migrants are human beings who symbolise all those rejected by globalisation, Pope Francis told a special mass on Monday, saying "the weakest and most vulnerable must be helped".
"These least ones are abandoned and cheated into dying in the desert," the pope told the mass to mark the sixth anniversary of the pope's visit to Lampedusa, where many asylum seekers arrive after a perilous sea journey from Libya.
"These least ones are tortured, abused and violated in detention camps, these least ones face the waves of an unforgiving sea," the pope told the mass, attended by 250 people including migrants, asylum seekers and rescue workers.
Italy has in recent weeks been trying to keep its ports closed to charity ships which have rescued migrants from the Mediterranean, usually shipwrecked after leaving war-torn and lawless Libya.
"They are persons, these are not mere social or migrant issues!" the pope said.
Italy's far-right Interior Minister Matteo Salvini has regularly used social media to attack migrants and the NGOs that help them.
"Migrants are first of all human persons, and... they are the symbol of all those rejected by today's globalised society," the pope said.
Francis travelled to Lampedusa in July 2013, four months after he was elected but before the 2013-2017 wave of migrant arrivals and shipwrecks, condemning "the globalisation of indifference" towards migrants.
Since then, the pope has repeatedly called for the welcoming of migrants fleeing war or poverty.
Unfortunately, he said, the outskirts of Italian cities were "densely populated with persons who have been thrown away, marginalised, oppressed, discriminated against, abused, exploited, abandoned, poor and suffering".