UNITED NATIONS — Antonio Guterres pledged Thursday to make the pursuit of peace in a conflict-torn world his “over-arching priority” after being elected the next secretary-general of the United Nations.

The former Portuguese prime minister and U.N. refugee chief told the 193 members of the U.N. General Assembly who elected him by acclamation that the United Nations has “the moral duty and the universal right” to ensure peace — and he will be promoting a new “diplomacy for peace” advocating dialogue to settle disputes.

Gutteres said he will do his best before taking the reins of the U.N. from Ban Ki-moon on Jan. 1 to prepare “to act as a convener, an honest broker, someone trying to bring people together” in conflicts and crises from Syria and Yemen to South Sudan.

“It’s high time to fight for peace,” he said, and make people understand that whatever divisions exist it’s more important to unite and end the suffering because of the risks for countries in conflict and the international community.

Guterres, who will become the ninth U.N. chief in the world body’s 71-year history, said he is not only fully aware of the challenges the United Nations faces but the limitations surrounding the secretary-general.

“The dramatic problems of today’s complex world can only inspire a humble approach, one in which the secretary-general alone neither has all the answers nor seeks to impose his views, one in which the secretary-general makes his good offices available … to help find solutions that benefit everyone involved.”

It was Guterres’ strong performance answering questions before the General Assembly, and his executive experience as prime minister and as the U.N. High Commissioner for Refugees from 2005-2015 that propelled him to first place among the 13 candidates vying for the job in the informal polls in the Security Council. After last week’s sixth poll, the council nominated him by acclamation.

At Thursday’s meeting, General Assembly President Peter Thompson introduced the resolution to elect Gutteres, said members wanted it adopted by acclamation, and banged his gavel in approval as diplomats broke into applause.

Guterres “embodies the highest standards of competence, integrity and leadership,” Thompson said.

Secretary-General Ban, recalling Guterres’ decade as the U.N.’s refugee chief, told the assembly that he is “best known where it counts most, on the front lines of armed conflict and humanitarian suffering.”

Ban noted that Guterres’ election was 10 years to the day after his own election in 2006, calling the ceremony “poignant for me.” But he told Guterres: “the people of the world are all looking forward to your tenure with confidence and excitement.”

Ambassador Samantha Power, speaking on behalf of the United States as the host country of the United Nations, called Gutteres “supremely qualified,” saying he will use the office to be “an independent force to prevent conflict and alleviate human suffering.”

She said the world’s nations are challenging the United Nations and the secretary-general to do more than they have ever done before.

For the U.N. to succeed, Power said, nation are asking Guterres to serve as a peacemaker, a reformer to streamline the U.N. bureaucracy, and an advocate rallying the world “to respond to humanitarian and man-made catastrophes, and defending the human rights of all people.”

Power stressed the importance of U.N. unity in selecting Guterres, especially in the often divided Security Council — a view echoed by Guterres who expressed hope that this unity can be channeled to take decisions to bring peace.

He said that in a world which is more and more multi-ethnic, multi-cultural and multi-religious, “diversity can bring us together not drive us apart.”

But Guterres said: “We must make sure that we are able to break this alliance between all those terrorist groups, or violent extremists on one side, and the expressions of populism and xenophobia on the other side. These two reinforce each other, and we must be able to fight both of them with determination.”