Pope Francis goes off script in Cuba to urge clergy to embrace poverty
Pope Francis delivers his Sunday Angelus prayer from the window of the apostolic palace overlooking St Peter's Square in the Vatican on August 30, 2015 (AFP Photo/Alberto Pizzoli)

Pope Francis abandoned his prepared speech Sunday at an evening prayer service in Havana to urge the clergy to embrace poverty and never forget "the most abandoned."

His face flushing in the tropical heat, he delved into a stern and lively impromptu address to hundreds of local priests, nuns and seminarians at the Cuban capital's cathedral on the second day of his visit to the Americas' only communist-ruled nation.

"Wealth makes us poor," he told them, warning they risked "ending up mediocre" if they forget "the smallest, the most abandoned, the sickest" to focus on budgets or management principles.

"Please, don't tire of forgiving, don't be afraid of mercy," said the pope, who is preparing to inaugurate a "holy year of mercy" in December.

In his prepared speech -- which Francis nevertheless arranged to have sent to the press -- he lashed out at backbiting and factionalism in the Church, which in two weeks will hold a synod on the family that has unleashed internal conflicts over sensitive issues such as divorce, homosexuality and unmarried couples.

He condemned "division into cliques" and urged the clergy "to speak straightforwardly, despite our disagreements and disputes, and not behind each other's backs."

But he added that spirited debate was healthy for the Church.

"Conflicts and disagreements in the Church are to be expected and, I would even say, needed," he said.

"Woe to those communities without a 'yes' and a 'no.' They are like married couples who no longer argue, because they have lost interest, they have lost their love."