Pope Francis on Friday strongly condemned the craving for material gains and power, telling world leaders gathered at the United Nations that greed is destroying the Earth's resources and aggravating poverty.

"A selfish and boundless thirst for power and material prosperity leads both to the misuse of available natural resources and to the exclusion of the weak and disadvantaged," he said in a speech to the General Assembly.

RELATED: PHOTOS: Pope Francis in New York

Francis, 78, called on government leaders to fight human trafficking, boost education for girls and end the destruction of the environment, which he warned is threatening the "very existence of the human species."

The Guardian quoted a portion of his speech that directly referenced the venue by citing the preamble to the UN charter: “The ideal of ‘saving succeeding generations from the scourge of war,’ and ‘promoting social progress and better standards of life in larger freedom’ risks becoming an unattainable illusion, or even worse, idle chatter which serves as a cover for all kinds of abuse and corruption. ”

The spiritual leader of the world's 1.2 billion Catholics, and the first pope from Latin America, Francis has often criticized unbridled capitalism in the two years of his papacy.

RELATED: Meet two Sikh leaders who will pray with Pope Francis at the 9/11 Memorial

The piece of legislation that received the most specific mention in his speech was the recent nuclear deal with Iran. “The recent agreement reached on the nuclear question in a sensitive region … is proof of the potential of political good will and of law,” he was quoted by The Guardian. “I express my hope that this agreement will be lasting and efficacious.”

The Argentine pontiff has caught the attention of well wishers on his six-day trip to the United States by riding in a tiny Fiat car, which was used in his journey from the UN to lower Manhattan. There, he will lead an inter-religious prayer service at the site of the World Trade Center attacks.

Reuters contributed to this story.