BEIJING, China (AP) — World Health Organization experts will visit the city of Wuhan, where the coronavirus was first detected in late 2019, at the start of their investigation into the origins of the pandemic, China said Tuesday.

Foreign Ministry spokesperson Zhao Lijian said the experts will arrive in Wuhan on Thursday. Other details of their schedule haven’t been announced and the central government’s National Health Commission offered no further information.

The visit has been expected for months. WHO chief Tedros Adhanom Ghebreyesus expressed frustration last week that arrangements were taking so long to finalise. After China announced the visit Monday, Tedros said the scientists, who come from several nations, will focus on how the coronavirus first jumped to people.

“Studies will begin in Wuhan to identify the potential source of infection of the early cases,” Tedros said.

China has rejected calls for an independent investigation while strictly controlling all research into the origins of the coronavirus and promoting fringe theories that the virus may have actually been brought to China from outside.

The culture of secrecy is believed to have delayed warnings about the pandemic, blocked the sharing of information with WHO and hampered early testing. There was considerable frustration among WHO officials over not getting the information they needed to fight the spread of the deadly virus, AP has found.

The virus’ origins have been the source of intense speculation, much of it centred around the likelihood that it was carried by bats and passed to humans through an intermediary species sold as food or medicine in traditional Chinese markets.

China largely brought the virus’ local spread under control last spring, but is currently dealing with a new outbreak in the province of Hebei adjacent to Beijing. Travel to and from three cities, including the provincial capital Shijiazhuang, Xingtai and Langfang south of Beijing, has been suspended and residents of some communities have been told to stay home for the next week.

Similar measures have been ordered around the country, particularly in Wuhan where 11 million people were placed under lockdown for 76 days last winter during the early days of the pandemic.

Hebei has also delayed meetings of the provincial People’s Congress and its advisory body that are usually held in February. It wasn’t clear when the meetings will be held.

Local authorities say several dozens of the more than 300 confirmed cases reported this year in Shijiazhuang appear to be linked to wedding gatherings.

One new case was also reported Tuesday in Beijing, where more than a dozen communities and villages have been put under lockdown, and one in the northeastern province of Heilongjiang, bringing China’s reported total to 87,591, including 4,634 deaths.

That outbreak comes amid measures to curb the further spread of the virus during next month’s Lunar New Year holiday. Authorities have called on citizens not to travel, ordered schools to close a week early and conducted testing on a massive scale.