Pope Francis on Saturday hammered home his message that European governments must do more to care for migrants crossing the Mediterranean, saying "those who risk their lives at sea do not invade, they look for welcome."

Closing a meeting of bishops and young people from around the Mediterranean in the French port city of Marseille, he added that migration is "a reality of our times, a process that involves three continents around the Mediterranean and that must be governed with wise foresight, including a European response."

The pope's remarks – given in front of President Emmanuel Macron, whose government plans tougher measures to control migration – follow his insistence on arrival in France on Friday that "people who are at risk of drowning when abandoned on the waves must be rescued."

The way Europe addresses large numbers of arrivals from the Middle East and North Africa has shot up the political agenda since last week, when thousands of people landed on the Italian island of Lampedusa over just a few days.

The pope also appeared to weigh in on French domestic politics, targeting two of Macron's projects in assisted dying and inscribing the right to abortion in the constitution.

Old people risk being "pushed aside, under the false pretences of a supposedly dignified and 'sweet' death that is more 'salty' than the waters of the sea," Francis warned.

He also spoke of "unborn children, rejected in the name of a false right to progress, which is instead a retreat into the selfish needs of the individual." (AFP)