The US will no longer have any involvement with the World Health Organization (WHO), President Donald Trump said on Friday (local time).
Last month, Trump suspended funding indefinitely while the US government conducted a review of the WHO's handling of the COVID-19 pandemic.
The US was the WHO's largest source of financial support.
"China has total control over the World Health Organization despite paying only $40 million per year compared to what the United States has been paying, which is approximately $450m a year," Trump told reporters in Washington on Friday.
"Because they have failed to make the requested and greatly needed reforms, we will be today terminating our relationship with the World Health Organization and redirecting those funds to other worldwide and deserving urgent, global public health needs."
Trump had previously criticised a WHO assessment in January which said there was no proof of human-to-human transmission - further research would show that was not the case.
Trump went on to say China ignored its reporting obligations to the WHO when the virus first broke out, an accusation China has denied.
"Countless lives have been taken and profound economic hardship has been inflicted all around the globe," he said.
"China's cover-up of the Wuhan virus allowed the disease to spread all over the world, instigating a global pandemic that has cost more than 100,000 American lives and over a million lives worldwide."
Trump's announcement follows months of him slamming the WHO and China for their handling of the coronavirus, which emerged in the Chinese province of Hubei late last year.