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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Voting that had been expected on Thursday will now be held Friday instead.
Police were called in amid fears the man may have been poisioned.
Williams is charged with first-degree murder without premeditation, a probation violation and for not having a valid driver’s licence.