President Donald Trump announced Monday he is withdrawing the US from the World Health Organization, a significant move on his first day back in the White House cutting ties with the United Nations’ public health agency and drawing criticism from public health experts.

The WHO is a United Nations agency that aims to expand universal health coverage, coordinates responses to health emergencies such as pandemics, and has a broad focus on healthy lives. It does not have the power to enforce health policy, but influences policy worldwide, especially in low-income countries.