Microsoft co-founder Bill Gates took to Twitter on Wednesday to criticize President Donald Trump’s decision to halt funding of the World Health Organization. He says the organization’s work is slowing the spread of COVID-19, and it can’t be erased. 

“Halting funding for the World Health Organization during a world health crisis is as dangerous as it sounds,” Gates tweeted. “Their work is slowing the spread of COVID-19 and if that work is stopped no other organization can replace them. The world needs @WHO now more than ever.”

Gates’ foundation has been outspoken on what is needed to stop the coronavirus pandemic. On April 2, he said the US needs a nationwide shutdown to curb the spread of the virus. Then on April 9 in an interview on CNBC, Gates said there needs to be an improvement in testing if the country wants to open back up.