Former Portuguese Prime Minister Antonio Guterres was sworn in as the ninth secretary-general of the United Nations on Monday. Guterres noted in a speech that he was taking office at a time when people across the world were losing confidence in their leaders and institutions.

"It is time to reconstruct relations between people and leaders - national and international - it's time for leaders to listen and show that they care about their own people and about the global stability and solidarity on which we all depend," Guterres said after reading the oath of office.

"It is time for the United Nations to do the same - to recognize its shortcomings and reform the way it works…The UN must be willing to change," he said.

Guterres promised that his tenure would focus on three key areas: streamlining the internal functions of the UN, cultivating peace, and promoting sustainable development. He also downplayed the power of the secretary-general in comparison to that of the member states.

The one-time UN High Commissioner for Refugees is taking over from the outgoing Ban Ki-moon.

Ban, who has been in office for the past decade, was given a standing ovation as part of his farewell on Monday.

"For me, the power of the United Nations was never abstract or academic. It is the story of my life," said the South Korean diplomat. Highlighting the role of the organization in his own life experience, he said that as boy growing up during the Korean War, "UN aid fed us. UN textbooks taught us. UN solidarity showed us we were not alone."

Antonio Guterres officially begins a five-year term on January 1.

es/jm (AP, dpa)