Donald Trump has severed ties with the World Health Organisation and confirmed he will fully withdraw all US funding.
The President has been openly critical of the international body for weeks over what he believes was an inadequate response to the outbreak of coronavirus in the Chinese province of Wuhan last year.
Speaking during a White House address on Friday, he claimed that Chinese officials had “ignored” reporting obligations to WHO and pressured the organisation to to mislead the public about COVID-19.
The virus has caused the deaths of more than 100,000 people in the US.
“We have detailed the reforms that it must make and engaged with them directly, but they have refused to act,” President Trump said.
“Because they have failed to make the requested and greatly needed reforms, we will be today terminating the relationship.”
The US is the largest source of financial support for WHO, which is expected to be severely damaged by the withdrawal of funding.
Instead, Trump says the money will be redirected towards “other worldwide and deserving urgent global public health needs”.
He noted America contributes about $450 million (£360 million) to the WHO, while China provides about $40 million (£32 million).
The President first proposed withdrawing funding from WHO in April – a move the Democrats deemed illegal without the approval of Congress. Others said that it would severely affect vaccine development efforts led by the organisation.
House Speaker Nancy Pelosi called the announcement “an act of extraordinary senselessness”.
Dr Stephen Griffin, associate professor in the School of Medicine, University of Leeds, said there was “no logic” in severing links during the middle of a global pandemic.
He added: “There is no logic to the move by President Trump to sever links with the WHO.
“Pandemics are, by definition, a global crisis. To not face Covid-19 with a united front seems futile.
“Given the scale of the outbreak in the US, this action appears nothing short of an attempt to refocus attention away from how this has been handled.”
Dr Gail Carson, director of network development at the International Severe Acute Respiratory and Emerging Infection Consortium, said that during a pandemic was not the time to make health political.
Dr Carson, a consultant in infectious diseases at the University of Oxford, added: “If there was a time not to make health political it is now, when the world is in the throes of a pandemic.
“Now is the time for solidarity and to stand together to end the pandemic as soon as we can and to save lives.
“Is this US government decision going to do good to all?
“WHO stands for the health of all of us and should not be ‘punished’ by any country in the middle of a pandemic because of an opinion, certainly not before any action review process has taken place.
“Now is not the time to weaken the world’s leading health agency, who has shown strong leadership with strong technical messages throughout this pandemic.”