The World Health Organization's chief hit back Monday at US President Donald Trump's reasons for pulling the United States out of the WHO — and again urged Washington to reconsider.

The United States is by far the WHO's biggest donor and its withdrawal will leave a major hole in the organization's budget and its ability to respond to global public health threats.

WHO director-general Tedros Adhanom Ghebreyesus went through, in turn, the reasons given by Trump's executive order to withdraw from the organization, signed within hours of his return to office on 20 January, and outlined what the UN health agency was doing in each field.

"We regret the decision and we hope the US will reconsider," Tedros told the opening of the WHO's executive board meeting.

Reforms and payments

Tedros balked at Trump's assertion in his executive order that WHO had failed "to adopt urgently needed reforms."

Over the past seven years, the WHO has implemented "the deepest and most wide-ranging reforms in the organization's history," he said.

Addressing Trump's claim that the WHO "demands unfairly onerous payments from the US," Tedros stressed that the organization had been working to broaden its donor base.

The WHO chief said shifting the balance away from the voluntary contributions, which make up the vast majority of the WHO's income, towards regular membership fees would address the "over-reliance" on major donors.

In response to the executive order's charge of the WHO "mishandling of the Covid-19 pandemic," Tedros highlighted the swift action taken by the organization from the very first signals of a "viral pneumonia" spreading in China to alert the world, publish guidance and protect populations.

"Of course there would be challenges and weaknesses" along the way, he said.

But Tedros insisted that WHO had taken steps to address those issues, and had created a host of new entities to improve the response like the Pandemic Fund and the mRNA Technology Transfer Hub, along with the new pandemic agreement being negotiated among WHO member states.

Finally, Trump's order charged the WHO had an "inability to demonstrate independence from the inappropriate political influence of WHO member states".

Tedros said the organization was impartial and tried to serve all countries, but when they make demands on the agency which are "not supported by scientific evidence... we say no, politely."