<p class="bodytext">A team of experts from the World Health Organization left quarantine in Wuhan on Thursday to begin a heavily scrutinised probe into the origins of the Covid-19 pandemic, after Washington urged a "robust and clear" investigation.</p>.<p class="bodytext">The group started a two-week quarantine on arrival on January 14 in the central Chinese city where the first known cluster of virus cases emerged in late 2019.</p>.<p class="bodytext">Wearing masks, they peered at the ranks of waiting media from the window of a bus which whisked them from the quarantine to another hotel on Thursday -- although it was not immediately clear when and where their investigation will start.</p>.<p class="bodytext">"So proud to graduate from our 14 days... no-one went stir crazy & we've been v productive," tweeted team member Peter Daszak, president of EcoHealth Alliance, a global NGO focused on infectious disease prevention.</p>.<p class="bodytext">The virus is believed to have come from bats and to have initially spread from a wet market in Wuhan where wild animals were sold as food.</p>.<p class="bodytext">The WHO insists the visit will be tightly tethered to the science of how the virus -- which has killed more than two million people -- jumped from animals to humans.</p>.<p class="bodytext">But in a sign of the political baggage attached to their mission, US President Joe Biden's new administration weighed in before the experts had even finished quarantine.</p>.<p class="bodytext">Speaking to reporters on Wednesday, new White House spokeswoman Jen Psaki said it was "imperative we get to the bottom" of how the virus appeared and spread worldwide.</p>.<p class="bodytext">Psaki voiced concern over "misinformation" from "some sources in China" and urged a "robust and clear" probe.</p>.<p class="bodytext">Beijing snapped back on Thursday, warning the United States to "respect facts and science, respect the hard work" of the WHO experts.</p>.<p class="bodytext">They must be allowed to work "free from political interference", Ministry of Foreign Affairs spokesman Zhao Lijian told reporters.</p>.<p class="bodytext">But in a mission dogged by delays and obfuscation from their Chinese hosts, it was not clear what the expert team will be allowed to see in Wuhan -- or what useful evidence remains a year after the outbreak in a country which has vigorously controlled the narrative of how the pandemic began.</p>.<p class="bodytext">The early days of the outbreak remain among the most sensitive topics in China today, with the Communist leadership seeking to stamp out any discussion that shows its governance in a poor light.</p>.<p class="bodytext">Beijing has also sought to seed doubt into the origin story, floating the unsubstantiated theory that the virus emerged elsewhere.</p>.<p class="bodytext">Another theory, amplified by former US president Donald Trump, is that it leaked from a laboratory in Wuhan where researchers were studying coronaviruses.</p>.<p class="bodytext">Relatives of Wuhan's coronavirus dead have called for a meeting with the team from the UN health agency, saying they have been facing new levels of official obstruction since the WHO team arrived.</p>.<p class="bodytext">According to official Chinese figures the virus killed nearly 3,900 in Wuhan, accounting for the vast majority of the 4,636 dead China has reported.</p>.<p class="bodytext">China is taking no risks in bringing a resurgence of the virus to heel, conducting anal swabs, localised lockdowns and cancelling flights as it makes travel before the Lunar New Year difficult.</p>
<p class="bodytext">A team of experts from the World Health Organization left quarantine in Wuhan on Thursday to begin a heavily scrutinised probe into the origins of the Covid-19 pandemic, after Washington urged a "robust and clear" investigation.</p>.<p class="bodytext">The group started a two-week quarantine on arrival on January 14 in the central Chinese city where the first known cluster of virus cases emerged in late 2019.</p>.<p class="bodytext">Wearing masks, they peered at the ranks of waiting media from the window of a bus which whisked them from the quarantine to another hotel on Thursday -- although it was not immediately clear when and where their investigation will start.</p>.<p class="bodytext">"So proud to graduate from our 14 days... no-one went stir crazy & we've been v productive," tweeted team member Peter Daszak, president of EcoHealth Alliance, a global NGO focused on infectious disease prevention.</p>.<p class="bodytext">The virus is believed to have come from bats and to have initially spread from a wet market in Wuhan where wild animals were sold as food.</p>.<p class="bodytext">The WHO insists the visit will be tightly tethered to the science of how the virus -- which has killed more than two million people -- jumped from animals to humans.</p>.<p class="bodytext">But in a sign of the political baggage attached to their mission, US President Joe Biden's new administration weighed in before the experts had even finished quarantine.</p>.<p class="bodytext">Speaking to reporters on Wednesday, new White House spokeswoman Jen Psaki said it was "imperative we get to the bottom" of how the virus appeared and spread worldwide.</p>.<p class="bodytext">Psaki voiced concern over "misinformation" from "some sources in China" and urged a "robust and clear" probe.</p>.<p class="bodytext">Beijing snapped back on Thursday, warning the United States to "respect facts and science, respect the hard work" of the WHO experts.</p>.<p class="bodytext">They must be allowed to work "free from political interference", Ministry of Foreign Affairs spokesman Zhao Lijian told reporters.</p>.<p class="bodytext">But in a mission dogged by delays and obfuscation from their Chinese hosts, it was not clear what the expert team will be allowed to see in Wuhan -- or what useful evidence remains a year after the outbreak in a country which has vigorously controlled the narrative of how the pandemic began.</p>.<p class="bodytext">The early days of the outbreak remain among the most sensitive topics in China today, with the Communist leadership seeking to stamp out any discussion that shows its governance in a poor light.</p>.<p class="bodytext">Beijing has also sought to seed doubt into the origin story, floating the unsubstantiated theory that the virus emerged elsewhere.</p>.<p class="bodytext">Another theory, amplified by former US president Donald Trump, is that it leaked from a laboratory in Wuhan where researchers were studying coronaviruses.</p>.<p class="bodytext">Relatives of Wuhan's coronavirus dead have called for a meeting with the team from the UN health agency, saying they have been facing new levels of official obstruction since the WHO team arrived.</p>.<p class="bodytext">According to official Chinese figures the virus killed nearly 3,900 in Wuhan, accounting for the vast majority of the 4,636 dead China has reported.</p>.<p class="bodytext">China is taking no risks in bringing a resurgence of the virus to heel, conducting anal swabs, localised lockdowns and cancelling flights as it makes travel before the Lunar New Year difficult.</p>