Pope Francis on Saturday urged European governments to welcome migrants instead of viewing them as invaders, striding into in a hugely sensitive political debate again inflamed by mass arrivals.

"Those who risk their lives at sea do not invade, they look for welcome," Francis said in a speech closing a conference of bishops and young people from around the Mediterranean in the French port city of Marseille.

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 pontiff added.

Francis' 35-minute speech drew a standing ovation from his audience, but his position on migration was unlikely to please French President Emmanuel

Macron and Interior Minister Gerald Darmanin were both present and planned stricter measures to control arrivals.

The pope's forceful interventions come as the migration debate has been stoked by mass arrivals on the Italian island of Lampedusa last week.

Speaking at a monument to people lost at sea on his arrival in Marseille on Friday, the pontiff had insisted that "people who are at risk of drowning when abandoned on the waves must be rescued".

He thanked aid groups for rescuing migrants in danger at sea, condemning efforts to prevent their work as "gestures of hate".