United Nations Secretary-General Antonio Guterres has warned that a global recession "is a near certainty".
He said current national responses to the coronavirus pandemic "will not address the global scale and complexity of the crisis."
"This is a moment that demands coordinated, decisive, and innovative policy action from the world's leading economies," Guterres told reporters via video conference. "We are in an unprecedented situation and the normal rules no longer apply."
"A global recession "perhaps of record dimensions" is a near certainty," he said.
The world's wealthiest nations poured unprecedented aid into the traumatized global economy today as coronavirus cases ballooned in the current epicentre, Europe, even as they waned at the pandemic's point of origin, China.
So far there have been almost 219,000 infections and more than 8,900 deaths.
"Our world faces a common enemy. We are at war with a virus," Guterres said. "I call on world leaders to come together and offer an urgent and coordinated response to this global crisis."
Guterres called on countries to scale up health spending and to help countries less prepared to tackle the crisis, including by supporting the efforts of the World Health Organisation.
He said that when it came to the global economy the liquidity of the financial system must be guaranteed and that banks must use their resilience to support their customers.
"G20 leaders have taken steps to protect their own citizens and economies by waiving interest payments. We must apply that same logic to the most vulnerable countries in our global village and alleviate their debt burden," he said.
Meanwhile, amid growing evidence of the damage already inflicted on the US economy by the pandemic, Treasury Secretary Steven Mnuchin is urging Congress to pass a $1 trillion emergency stimulus package immediately.
Many economists now say the United States is already in a deep recession, and the latest economic data show a surge in layoffs and manufacturing shutdowns rippling across the country as the government clamps down on gatherings and calls for strict social distancing to stop the virus from spreading further.
Forecasts now show the world's largest economy will crater, contracting between 12 to 14% in the April-June period.
President Donald Trump has pledged to "go big" to support the economy, and his administration has eschewed the traditional Republican aversion to debt and deficits.
