World Health Organization inspectors will visit a laboratory in China's Wuhan city on Wednesday that American officials suggested could have been the source of the coronavirus, according to state media.
The inspection of the Wuhan virology institute, which conducts research on the world's most dangerous diseases, will be one of the most-watched stops on the team's probe into the origins of the Covid-19 pandemic.
The sensitive mission, which China had delayed throughout the first year of the pandemic, has a remit to explore how the virus jumped from animal to human.
But questions remain over what the experts can hope to find after so much time has passed.
Scientists think Covid-19 — which first emerged in Wuhan and has gone on to kill more than two million people worldwide — originated in bats and could have been transmitted to people via another mammal.
But there are no definitive answers so far.
There was speculation early in the pandemic that the virus could have accidentally leaked from the biosafety lab in Wuhan, although there was no evidence to back up that theory.
Then-US president Donald Trump and his supporters seized on those rumours and amplified them with conspiracy theories that China deliberately leaked the virus.
Chinese state broadcaster CGTN said Wednesday the WHO team would "visit the national biosafety laboratory and exchange ideas with experts of the institute on their daily work, international scientific cooperation, anti-epidemic efforts and contribution".
China has faced criticism at home and abroad for playing down the initial outbreak and concealing information when it first emerged in Wuhan in December 2019.
But WHO team member Peter Daszak told journalists on Tuesday the mission was proceeding "very well", as the group was driven into an animal disease control centre.
China is also determined to put the focus on its recovery from the outbreak, and the WHO team toured a propaganda exhibition celebrating China's recovery from the pandemic in Wuhan on Saturday.
On Sunday the team went to the market in Wuhan where one of the first reported clusters of infections emerged over a year ago, which Daszak tweeted was a "critical" stop.