Pope Francis on Friday urged Europe to "tear down" the walls being built to keep out migrants and to embrace a radical "social economy" serving the many not the few.

Invoking the memory of the EU's founding fathers and the aftermath of World War II, the pontiff said they had "dared to change radically the models" that had led to war.

"Today more than ever, their vision inspires us to build bridges and tear down walls," he added in a speech marking his acceptance of the EU's Charlemagne Prize.