Updated at 3:30 p.m. ET

The COVID-19 pandemic is testing the world – and humanity is failing because of a lack of leadership and unity, the head of the World Health Organization declared in a passionate speech Thursday.

"How is it difficult for humans to unite and fight a common enemy that is killing people indiscriminately?" WHO Director-General Tedros Adhanom Ghebreyesus asked at a briefing in Geneva, his voice rising with emotion.

"Are we unable to distinguish or identify the common enemy?" he asked.

The world's lack of solidarity — not the coronavirus — is the biggest threat we face, Tedros said, adding that divisions among countries and people give an advantage to a virus that has been holding the world hostage for months.

The WHO director-general spoke about the lack of leadership two days after President Trump began the formal process of pulling the U.S. out of the World Health Organization. That move is expected to become final next June.

Trump has frequently targeted WHO during the COVID-19 crisis, accusing the international body of withholding information and having an overly close relationship with China. WHO officials said they have shared data about the health emergency as soon as possible.

"Please don't politicize this virus," Tedros said in April after Trump threatened to halt U.S. funding for WHO. Using a pandemic to score political points, he said, would only result in "many more body bags."

COVID-19 has killed more than 550,000 people worldwide – and the global total of reported cases has surpassed the 12 million mark, according to the latest tally from Johns Hopkins University.

When Tedros declared the disease a pandemic on March 11, some 4,000 people had died and there were fewer than 120,000 confirmed cases worldwide. But the WHO chief warned that the numbers would go higher.

In the months since, Tedros has repeatedly called for countries to fight the pandemic with unity and common cause. He has also criticized governments for failing to take measures to stop the spread of the virus.

Here is the full section of Tedros' remarks that prompted his show of emotion:

"My friends, make no mistake. The greatest threat we face now is not the virus itself.

"Rather, it's the lack of leadership and solidarity at the global and national levels. That's why I said earlier, each and every individual should reflect. This is a tragedy that is forcing us to miss many of our friends and lose many lives. And we cannot defeat this pandemic as a divided world.

"The COVID-19 pandemic is a test of global solidarity and global leadership. The virus thrives on division, but is thwarted when we unite.

"How is it difficult for humans to unite and fight a common enemy that is killing people indiscriminately? Are we unable to distinguish or identify the common enemy? Can't we understand that the divisions and the cracks between us are an advantage for the virus. I think I do not need to remind you because we all know that these are the basics.

"My hope is that the defining crisis of our age will likewise remind all people that the best way forward – and the only way forward – is together. These are the basics, but the time-tested truth. 'Together' is the solution unless we want to give the advantage to the enemy, to the virus, that has taken the world hostage, and this has to stop.

"I thank you."

Copyright 2021 NPR. To see more, visit https://www.npr.org.