BERLIN: The head of the World Health Organisation said investigations into the origins of the COVID-19 pandemic in China were being hampered by the lack of raw data on the first days of its spread there.

"We ask China to be transparent and open and to cooperate," Director-General Tedros Adhanom Ghebreyesus told a news conference on Thursday.

"We owe it to the millions who suffered and the millions who died to know what happened," he said.