Roughly one in 10 people may have been infected with the coronavirus, leaving the vast majority of the world's population vulnerable to the Covid-19 disease it causes, the World Health Organization said on Monday.
Mike Ryan, the WHO's top emergency expert, was addressing the agency's Executive Board, where the United States made a thinly veiled swipe at China for what it called a "failure" to provide accurate and timely information on the outbreak.
But Zhang Yang of China's National Health Commission, said: "China has always been transparent and responsible to fulfil our international obligations." China maintained close contacts with all levels of the UN health agency, she added.
Ryan said that outbreaks were surging in parts of southeast Asia and that cases and deaths were on the rise in parts of Europe and the eastern Mediterranean region.
"Our current best estimates tell us about 10 percent of the global population may have been infected by this virus. It varies depending on country, it varies from urban to rural, it varies depending on groups. But what it does mean is that the vast majority of the world remains at risk," Ryan said.
"We are now heading into a difficult period. The disease continues to spread," he said.
The WHO and other experts have said that the virus, believed to have emerged in a food market in the central Chinese city of Wuhan late last year, is of animal origin.
The WHO has submitted a list of experts to take part in an international mission to China to investigate the origin, for consideration by Chinese authorities, Ryan said, without giving details.
US assistant health secretary Brett Giroir said that it was critical that WHO's 194 member states receive "regular and timely updates, including the terms of reference for this panel or for any field missions, so that we can all engage with the process and be confident in the outcomes".
Germany, speaking for the EU, said the expert mission should be deployed soon, with Australia also supporting a swift investigation.
Meanwhile, Alexandra Dronova, Russia's deputy health minister, called for an evaluation of the legal and financial repercussions of the Trump administration announcing the US withdrawal from the WHO next July.
The United States will not pay some $80 million it owes the WHO and will instead redirect the money to help pay its UN bill in New York, a US official said on Sept. 2.