Speaking in the Rose Garden at the White House, the US president Donald Trump said he wanted to redirect funds to other organisations in an anti-China address over the coronavirus pandemic.
He accused the WHO of failing to adequately respond to COVID-19 because China has “total control” over the global organisation.
He said Chinese officials “ignored” their reporting obligations to the WHO and pressured the group to mislead the world when the virus was first discovered.
It comes after weeks of criticism of the WHO by Mr Trump who has accused the organisation of not acting fast enough on the coronavirus outbreak.
The US is the biggest single contributor to the WHO, paying in around $450m (£360m) a year, with Mr Trump saying that China only contributed around $40m (£32m).
His move to cut ties with the organisation is expected to significantly weaken it while in the midst of the COVID-19 pandemic.
In his address, Mr Trump again blamed China for the COVID-19 outbreak, calling it the “Wuhan virus”, and said the country is responsible for more than 100,000 US deaths.
He also criticized China over its stance on Hong Kong, saying the city is no longer sufficiently autonomous to warrant special treatment from the US.
He said he will revise US travel advice to the region, warning of increased risk of surveillance.
The US will also take steps to sanction officials from Hong Kong who have been involved in “eroding” the autonomy of the region.
China is set to introduce legislation in Hong Kong that would crack down on the anti-government protests in the city.
It has prompted concerns that Beijing is chipping away at the “one country, two systems” principle, that outlines the region’s autonomy.
It was expected that Mr Trump would also use his news conference to address the death of George Floyd, whose death in police custody has sparked widespread protests in the US.
Mr Trump had quipped that “when the looting starts, the shooting starts” following riots in Minneapolis where Mr Floyd died.
However, the president left the stage before taking any questions from the press.