Vatican City (AFP) - Pope Francis on Saturday decried low birth rates in Europe and urged more help for young people preparing their future path in society.

"A Europe that rediscovers itself as a community will surely be a source of development for herself and for the whole world," the pope told (Re)Thinking Europe – a project sponsored by the European bishops' conference (COMECE).

Europe is suffering, the pontiff said, from "a period of dramatic sterility. Not only because Europe has fewer children, and all too many were denied the right to be born, but also because there has been a failure to pass on the material and cultural tools that young people need to face the future."

The Argentinian pontiff described the European Union as a tired "grandmother, no longer fertile and vibrant," in a 2014 address to the European Parliament.

On Saturday, he said he found Europe to be "increasingly distinguished by a plurality of cultures and religions" but warned of the dangers of erecting "walls of indifference and fear" when it came to assimilating migrants who "are more a resource than a burden."

For Francis, "leaders together share responsibility for promoting a Europe that is an inclusive community," as it looks to meet challenges including the "imbalances caused by a soulless globalisation."

Among the pope's audience were European Commission vice-president Frans Timmermans and EU parliament chief Antonio Tajani.

They heard Pope Francis insist that Europe "is not a mass of statistics or institutions, but is made up of people " who should not be "reduced to an abstract."