The United States will terminate its relationship with the World Health Organization (WHO), President Trump said in a press conference today.

“China has total control over World Health Organization,” Trump said. “We have detailed to them the reforms that they must make and engaged with them directly but they have refused to act.”

Trump had previously frozen funding to the WHO, claiming that the organization bowed to pressure from China and was overly trusting on their early information about the spread of the coronavirus. He also took issue with the WHO’s criticism of travel bans.

Still, severing ties with the organization is a drastic step. Experts say that if the US severs ties with the WHO, there could be catastrophic consequences to global public health. The US contributes hundreds of millions of dollars to its efforts. “It’s surreal to even be having this conversation, since it’s so hard to get one’s head around the massive implications,” Rebecca Katz, director of the Center for Global Health Science and Security at Georgetown University, told Nature this week.

The action could also impair the global response to COVID-19. The WHO is the central coordinating body for global public health emergencies. It’s currently organizing an international clinical trial investigating drugs that could treat COVID-19, and was pivotal in spurring early response to the disease, declaring a global public health emergency in January. The organization also supports the pandemic response in under-resourced countries.

Nearly 6 million people around the world have contracted the virus, and over 360,000 have died.