The chief of the World Health Organization (WHO) hit back Wednesday at criticism from U.S. President Donald Trump, and called on the U.S. and China to come together to fight the novel coronavirus.

Tedros Adhanom Ghebreyesus at a WHO video-press conference said: “We are asking to quarantine politicizing COVID-19,” and asserted that politicians should focus on saving lives.

“The focus of politicians should be to save their people….Please don’t exploit this virus,” he noted.

Remarks of Ghebreyesus came in response to questions by journalists regarding Trump’s tweet on Tuesday when the U.S. president criticized the WHO for being “China-centric”.

Read more: WHO urges US, China to combine efforts to fight virus