Pope Benedict XVI said the global phenomenon of immigration represents a social emergency that must be faced with a sense of responsibility and humanity.

He called on richer countries to be attentive especially to the needs of illegal immigrants, but said immigrants themselves must respect "the duty of legality that is valid for everyone."

The pope made the remarks at his noon blessing in Castel Gandolfo Aug. 31, in a courtyard packed with cheering pilgrims. His comments came as Italy and other Mediterranean countries experienced an annual summer influx of clandestine immigrants arriving from Africa by boat.

In late August, some 70 Africans were believed to have drowned between Malta and Sicily when their boat capsized. The pope said it was another example of immigrants' hopeful passage turning into tragedy.

While migration always has been a characteristic of human society, he said, "the emergency in which it has been transformed in our time requires our solidarity and demands an effective political response."

He said host countries should develop better structures and programs to meet the needs of illegal immigrants, and organizations dealing with such immigrants should continue their work with a sense of responsibility and a humanitarian spirit.

The countries of origin also have a responsibility to remove the causes of people leaving and to "cut down at the roots every form of criminality" associated with emigration, he said. He apparently was referring to illegal trafficking and prostitution rings.

The pope said immigrants themselves need to be made more aware of the value of their own lives, in light of the very high risks they run in the effort to improve their conditions.

In other more general remarks, the pope spoke about the Christian duty to try to improve the state of affairs in the modern world, "where forces that divide and destroy seem to dominate."

Christ's crucifixion opened the way to salvation, he said, but "the struggle is not over."

"Evil exists and resists in every generation, even, as we know, in our own days. What are the horrors of war, the violence against innocents, poverty and injustice that afflict the weak, if not the opposition of evil to the kingdom of God?" he said.

He urged Christians to respond as Jesus did, with the strength of love that overcomes hatred.

---CNS