Former Portuguese prime minister Antonio Guterres was sworn in as the ninth secretary-general of the United Nations on Monday, at the 60th plenary meeting of the UN General Assembly. “It is time to reconstruct relations between people and leaders,” he said while taking his oath of office.

He was officially appointed to the post by the 193-member group on October 13, after unanimously adopting the resolution by acclamation. The UN Security Council had selected the 67-year-old to succeed Ban Ki-moon at a meeting of its 15 members on October 5.

Guterres will take over the post after Ban’s tenure ends on December 31. The Portuguese leader’s term as secretary-general of the UN will continue till December 31, 2022.

The former prime minister of Portugal had served as the UN high commissioner for refugees from 2005 to 2015. After his selection was announced last week, he had said he would work for those most vulnerable, including victims of conflict, human rights violations, poverty and terrorism. Ban had described his selection as “superb”.