Updated

Pope Francis says while fear of migrants is "legitimate," it's a sin if that causes hostility.

Francis invited migrants, refugees, asylum-seekers, newly-arrived immigrants and second-generation immigrant families to a special Mass he celebrated Sunday in St. Peter's Basilica.

He noted that some local communities fear new arrivals will disturb the established order. He says that while that's "comprehensible from a human point of view," it is a sin if these fears "compromise respect and generosity" and "feed hostility and rejection" of those different from us.

In his almost five-year-old papacy, Francis has stressed Christianity's mission, in following Jesus, to welcome vulnerable and marginalized people.

His focus comes as wealthier countries, including several European Union nations and the U.S., are intent on increasing physical or legal barriers to migrants.