The World Health Organization on Thursday denounced accusations against the organization made by United States Secretary of State Mike Pompeo as "untrue and unacceptable".

Pompeo launched an extraordinary attack on the WHO during a private meeting in the United Kingdom, accusing it of being in the pocket of China and responsible for "dead Britons" who passed away during the COVID-19 pandemic, the Guardian reported on Tuesday.

Pompeo told the audience that he believed the WHO was a "political not a science-based organization" and accused the WHO Director-General Tedros Adhanom Ghebreyesus of being too close to Beijing. He added that he was saying "on a firm intelligence foundation, a deal was made" with China to allow Tedros to win election in 2017.

"The comments are untrue and unacceptable and without any foundation for that matter," Tedros told a virtual news conference from Geneva.

He said the focus of the entire organization is on saving lives, and that the WHO would not be distracted by the comments.

Tedros pointed out that one of the greatest threats the world faces is the continued politicization of the pandemic. "And I have said it many times: COVID politics should be quarantined," he said.

He appealed all nations to work together, saying that "politics and partisanship have made things worse".

Tedros' response was followed by some emotional comments from his colleagues, which is unusual for these briefings.

Maria Van Kerkhove, the WHO's technical lead on COVID-19, said she wanted to speak as an American and as a proud WHO employee.

"I have the honor and privilege to sit next to Dr Tedros and Dr Mike Ryan, I don't know for how many days, during the pandemic. And I have never been more proud to be WHO," she said, with an emotional tone.

Tedros, Van Kerkhove and Ryan, executive director of the WHO Health Emergencies Program, have been the key voices at WHO news briefings in the past months.

Van Kerkhove said she saw first hand the work of Tedros, Ryan and WHO teams all over the world. "We are firmly focused on saving lives... We will not be distracted," she said.

Ryan noted that many at the WHO have worked seven days a week and 20 hours a day in the past seven months, and many have been sent into harm's way.

"And many of us have spent months and years on the frontline, risking our lives, worrying our families for decades in this fight for social justice," he said.

Ryan also said that he is proud to sit by the side of Tedros in doing the work of saving lives and in the service of the people of the world.

"We are proud, proud to be WHO. We will remain so. We will serve the people of the world regardless of what said about us," he said.

WHO spokeswoman Margaret Harris, who moderated the news briefing, broke the usual practice to voice her views.

"I am not meant to say anything. But proud to be WHO now more than ever," she said.

The US began its withdrawal from the WHO early this month, in what many believe to be a move to shift the blame for the poor pandemic response at home. The US has been the worst hit by the pandemic, with more than 3.8 million cases and 140,000 deaths according to a WHO report on Wednesday.