Pope Francis on Friday criticised the inordinate desire for wealth and power in a speech to a huge gathering of world leaders at the United Nations.

The pontiff, who started the New York leg of his U.S. visit on Thursday, addressed poverty, environment and climate change during his speech that also marked the start of a UN sustainable development summit.

The summit is set to launch the UN’s post-2015 development goals to end extreme poverty, fight social inequality and fix climate change by 2030.

The pontiff,in remarks translated from Spanish, said, “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 urged global financial institutions to end “oppressive lending systems” that subject many to greater poverty, exclusion and dependence.

Pope Francis became the fourth pontiff to address the world body while visiting the United States.

The head of the Catholic Church warned UN member countries against being “nations united by fear and distrust,” calling laws based on the threat of mutual destruction as “self-contradictory and an affront to the entire framework of the UN.”

“We cannot permit ourselves to postpone certain agendas for the future. The future demands of us critical and global decisions in the face of worldwide conflicts which increase the number of the excluded and those in need,” he said.

If the UN’s charter is perceived “as an instrument to be used whenever it proves favorable,” he said, “a true Pandora’s box is opened, releasing uncontrollable forces which gravely harm defenseless populations, the cultural milieu and even the biological environment.”

Announcing the pontiff, UN Secretary-General Ban Ki-moon said, “In no other hall – from no other platform – can a world leader speak to all humanity.”

“Never in our 70-year history has the United Nations been honored to welcome a pope for the opening of the General Assembly. And never in papal history has the head of the Catholic Church addressed such an array of world leaders.”

Approximately 150 heads of state and government are to join the annual general debate at General Assembly beginning Sept. 28.

Prior to his address, Francis met with UN staff, telling them their roles are very important.

“Your devoted work not only contributes to the betterment of the United Nations, it also has great significance for you personally, for how you work expresses your dignity and the kind of persons you are,” he said in English. (AA)

•Photo shows Pope Francis delivering his speech . . . yesterday at the UN Headquarters in New York , USA.