U.S. President Donald Trump threatened to indefinitely suspend aid to the World Health Organization (WHO) unless it agreed to reforms within 30 days, and to rethink United States membership in the organization.

Last month, Trump suspended U.S. payments to the WHO, accusing it of spreading China’s “disinformation” about the coronavirus epidemic, while officials at the WHO refuted the allegation and China said it was open and clear.

“If the WHO does not commit to major substantive improvements within the next 30 days, I will make my temporary freeze of United States funding to the WHO permanent and reconsider our membership,” Trump told its chief, Tedros Adhanom Ghebreyesus, in a letter posted on Twitter.

Trump said earlier in his handling of the virus that the WHO had “done a very sad job” and that he would make a decision on U.S. funding soon.

Trump said in his letter that the only way forward for the body as if it could show independence from China, adding that his administration had already begun negotiations with Tedros on reforms.

The WHO said on Monday that an independent analysis of the global response to the virus would begin as soon as possible and that it had earned funding and a strong pledge of funds from China, in the spotlight as the pandemic’s origin.

More than 4.75 million people worldwide were officially infected and 314,414 died.

In 2019, the US contributed more than $400 million to the WHO, or around 15 percent of the organization’s budget. And Washington has already paid around $58 million to the WHO this year, senior Trump administration officials said last month, half of what it expects to pay for 2020 – known as an appraised donation.