The COVID-19 pandemic has exposed the world's vulnerability to crises all due to a lack of global cooperation, said World Health Organization (WHO) Director-General Tedros Adhanom.

Tedros made the remarks in at a COVID-19 media briefing on Thursday in Geneva, Switzerland.

"The COVID-19 pandemic has changed our world. It has stress tested our political, economic, cultural and social infrastructure," he said.

The WHO chief noted that the world had focused on averting other tragedies at the expense of potential health and climate issues.

"The world spends billions every year preparing for potential terrorist attacks but we've learned lessons the hard way that unless we invest in pandemic preparedness and the climate crisis, we leave ourselves open to enormous harm," said Tedros.

The 55-year-old's remarks come as the world's COVID-19 infections exceed 18.8 million with a death toll of over 708,000, according to data from the U.S.-based Johns Hopkins University.

"No country has been spared. Low, middle and high-income countries have all been hit hard," said Tedros.

The WHO chief reiterated calls for unity in the fight against the pandemic, urging world leaders to "choose the path of cooperation and act now to end this pandemic!"