GENEVA (REUTERS) - The World Health Organisation (WHO) is preparing to launch an appeal soon for more than US$1 billion (S$1.42 billion) to fund operations against the Covid-19 pandemic through year-end, diplomats told Reuters on Thursday (April 9).

It comes against the backdrop of a salvo lobbed by US President Donald Trump against the WHO over its handling of the Covid-19 pandemic and suggestions from his administration it might re-evaluate US funding.

The UN agency needs more resources than ever as it leads the global response against the disease that has infected 1.4 million people and killed 85,000, diplomats and experts say.

WHO Director-General Tedros Adhanom Ghebreyesus, in a speech to diplomats on Thursday issued by the WHO, said it would release its latest plan "in the coming days".

It follows the WHO's first three-month appeal for US$675 million through April.

"It will be well over US$1 billion, maybe several billion," a Western envoy said. Another diplomat following the discussions said that the appeal would be at least US$1 billion.

A WHO spokesman, asked about this figure, had no immediate comment.

Dr Tedros gave a strident defence of WHO's work on Wednesday, a day after Mr Trump accused it of being "China centric".

US Secretary of State Mike Pompeo later said Washington was re-evaluating US funding to the body, saying international organisations utilising US taxpayer money needed to deliver on their goals.