UNITED NATIONS, Nov. 17 (Xinhua) -- United Nations Secretary-General Antonio Guterres on Tuesday called on the Group of 20 (G20) countries to fill the financing gap of 28 billion U.S. dollars needed to fund the Access to COVID-19 Tools Accelerator (ACT-Accelerator) and its COVAX facility.

In a letter to G20 leaders before they meet on Nov. 21, the UN secretary-general said that "as we tackle this unprecedented pandemic, the world needs unprecedented leadership that is united in its quest to respond to the crisis and recover better."

ACT-Accelerator, or the Global Collaboration to Accelerate the Development, Production and Equitable Access to New COVID-19 diagnostics, therapeutics and vaccines, is a G20 initiative announced by pro-tem Chair Mohammed al-Jadaan on April 24.

Guterres said that recent positive early results on COVID-19 vaccine trials "have added a new sense of urgency to the need for equitable access to vaccines, diagnostics and therapeutics."

"It is also vital to invest in health systems accessible to all, including through Universal Health Coverage," he added.

On extreme poverty, the UN chief said that an additional 115 million people are at risk of falling into extreme poverty and acute hunger could almost double, affecting the lives of more than a quarter of a billion people.

"I call on the G20 to support implementation of social protection floors for all, regardless of age, gender, religion, origin, migration status or sexual orientation, including for those in the informal and invisible care economy," said Guterres.

Guterres said that the COVID-19 pandemic "has laid bare systemic fragilities in our societies, our global economic system and the frameworks that govern the international system."

He said that the G20's early response was crucial in easing the social and economic fallout from the pandemic, but he stressed that it now needs to scale up ambition and deliver bolder measures to enable developing countries to address the crisis effectively and to prevent the global recession from becoming a global depression.

The UN chief also noted that the world needs "unprecedented leadership that is united in its quest to respond to the crisis and recover better."