In his first "Urbi et Orbi" (to the city and the world) message, Francis also called for peace between Israelis and Palestinians, an end to the civil war in Syria, and political solutions to conflicts in several African countries.
The former Cardinal Jorge Bergoglio of Argentina also condemned the "iniquitous exploitation of natural resources" and urged everyone to be "guardians" of creation.
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UKIP leader Paul Nuttall is set to contest the Stoke Central by-election later this year according to ITV Central's Political Correspondent
Jeremy Corbyn has accused Theresa May of producing a "bargain-basement Brexit" plan and "demeaning" the UK's European standing.
The family said that there will "always be a welcome in Wales" for the former intelligence analyst and whistleblower.