Experts from the World Health Organization (WHO) are going to China this weekend to prepare for an international mission later to identify the zoonotic source of COVID-19, WHO Director-General Tedros Adhanom Ghebreyesus said on Tuesday.

Speaking at a virtual media briefing, Tedros said, "all preparations have been finalized and WHO experts will be traveling to China this weekend to prepare scientific plans with their Chinese counterparts for identifying the zoonotic source of the disease."

Tedros specified that the experts will develop the scope and terms of reference for a WHO-led international mission, whose objective is to advance the understanding of animal hosts for COVID-19 and ascertain how the disease jumped between animals and humans.

"Identifying the origin of emerging viral disease has proven complex in past epidemics in different countries. A well planned series of scientific researches will advance the understanding of animal reservoirs and the route of #COVID19 transmission to humans," Tedros said later on Twitter after the media briefing. 

"This process is an evolving endeavor which may lead to further international scientific research and collaboration globally," Tedros tweeted.

At a press conference on Wednesday, the Chinese Foreign Ministry also confirmed the WHO's trip, saying the Chinese government has agreed on the trip, during which experts from the WHO are expected to cooperate with Chinese scientists and medical experts on matters related to the zoonotic source of COVID-19. 

"We have a basic consensus with the WHO. The identification on the zoonotic source of COVID-19 is a scientific issue," said Zhao Lijian, a spokesperson from the ministry, adding that scientists should carry out international scientific research on the issue.

The WHO also believes that the identification is a continuous process and may involve multiple countries and regions. The organization will conduct similar visits in other countries and regions as needed, said Zhao. 

Michael Ryan, executive director of the WHO Health Emergencies Program, told the media briefing that answers to questions concerning the zoonotic source of a disease can sometimes be elusive, like in the cases of Ebola, MERS and SARS, which have taken quite some time as well as a meticulous multi-sectoral approach. 

In the case of COVID-19, Ryan said identifying the zoonotic origin could involve the wild animal kingdom, the farmed animal kingdom, as well as the interfaces between those animals and humans. 

"Understanding that the narrative and the pathway by which this virus entered the human population is extremely important, but it's not always a straightforward process of being able to get that answer," he said.