Defending migrant rights has become a key theme of his papacy.
Amid tension over North Korea, Pope Francis has warned of the threat of nuclear war during his last service of the year.
Pope Francis has used his annual World Day of Peace address in the Vatican to "give voice" to the world's migrants and refugees most in need.
He complained that 2017 had been squandered and abused.
All Sources: Deutsche Welle Deutsche Welle