China, Qatar, Switzerland and others have pledged over $170 million for the World Health Organization (WHO) at its assembly on Tuesday.

States have also accepted a hike in their fees to help offset the expected loss of top donor the United States.

"I am grateful to every member state and partner that has pledged towards the investment round," Dr Tedros Adhanom Ghebreyesus, the director-general of WHO, said in a statement.

He added: "In a challenging climate for global health, these funds will help us to preserve and extend our life-saving work."