President Donald Trump has been criticized at home and abroad after announcing he is ending US ties with the World Health Organization (WHO).
The EU urged him to reconsider the decision, while Germany’s health minister called it a “disappointing setback for international health”.
The head of the US Senate’s health committee, a Republican like Mr Trump, said now was not the time to leave.
Mr Trump said the WHO had failed to hold China to account over coronavirus.
The WHO, a UN agency that helps countries promote healthcare and tackle outbreaks of disease, has faced regular criticism from the US president over its handling of the outbreak.
He suspended US funding to the WHO last month and on Friday permanently halted the payment, which last year stood at more than $400m (£324m; €360m), the largest single contribution at around 15% of its total budget.