UNITED NATIONS - United Nations Secretary-General Antonio Guterres said on Monday that international cooperation is the only way to defeat the COVID-19 pandemic and the climate emergency.

"International cooperation is the only way to defeat the COVID-19 pandemic, the climate emergency, rising inequality and the spreading of hatred," the UN chief told an informal plenary meeting of the UN General Assembly to commemorate United Nations Day, which falls on Oct 24 each year.

"At this time of such colossal challenge, I welcome the General Assembly's declaration of commitment to reinvigorate multilateralism," said the secretary-general. "I look forward to an inclusive and insightful effort that will strengthen global governance and how the world responds to current and future challenges."

Guterres urged the international community to "build on the achievements of the United Nations across its history."

"And we can be inspired by the conversation we conducted this year to mark this milestone, and which took a revealing snapshot of our world in 2020 - and gave voice to the hopes and ideas of people across the globe. We measure the success of the United Nations by the lives we save, the suffering we ease, the peace we build, the opportunities we create, and the rights we protect," said the secretary-general.

"The women and men of the United Nations strive to bring that work to life around the clock and around the world," he added.

The UN chief hailed the spirit of UN personnel, noting the spirit "has fueled us for 75 years, and will guide us through the pandemic and beyond."

"We will never, ever give up in our mission and in our work to fulfil the enduring vision of the Charter," he said.

United Nations Day is observed on Oct 24 every year since 1948. The day marks the anniversary of the entry into force in 1945 of the UN Charter, which is the founding document of this non-partisan institution that has been working toward global peace and equality.