António Guterres has been sworn in as the ninth United Nations Secretary-General.

He replaces Ban ki-Moon as the top UN official. Ban ki-Moon will vacate the office next month.

António Guterres is a former Prime Minister of Portugal, and former UN High Commissioner for Refugees.

He took the oath of office on Monday following the Assembly’s tribute to Secretary-General Ban Ki-moon, who steps down at the end of this month after leading the global Organization for the past 10 years.

During his swearing in ceremony, Mr Guteres pledged to reposition development at the center of the UN’s work and ensure that the UN change to effectively meet the numerous challenges facing the international community.

He said his plan is to effect change on the bureaucratic processes within the United Nations, so that it acts quickly, efficiently and effectively on delivery.

On peacekeeping efforts, Mr. Guteres says there needs to be clarity on the scope of UN peacekeeping missions.

He said the UN is tasked with peacekeeping in places where there is no peace to keep.

On sustainable development, Mr Guteres says his reform agenda will look at UN support to Member States in achieving the Sustainable Development Goals.

Mr Guteres also pledged to use his time as Secretary-General to promote peace and mutual cooperation among members.

After being sworn in by General Assembly President John William Ashe, Guterres addressed the 193 member nations, saying the world body must work to simplify, decentralize and make more flexible its sprawling bureaucracy.

“It benefits no one if [it] takes nine months to deploy a staff member to the field,” he said.

“The United Nations needs to be nimble, efficient and effective. It must focus more on delivery and less on process, more on people and less on bureaucracy.”

António Guterres was appointed by the UN General Assembly on 13th October this year in what was the culmination of an historic process, where each candidate vying for the leadership position debated in public.

Mr Guteres visited South Sudan in 2012 as UN High Commissioner for Refugees to help the government reintegrate South Sudanese who were returning from Sudan.

In 2014, he wrapped up a 2 days visit where he called for solidarity with the people of South Sudan so that they forge peace from within.