Chinese police say they have found a new virus circulating in China that killed at least 100,00 people, including about 40,000 in the cities of Shanghai and Shenzhen, and the death toll is likely to rise.
Authorities said on Tuesday that they had identified the new strain, which appears to have originated in southern China.
They said that in all the cases, the new virus was able to evade anti-virus testing and spread rapidly across a large area, with many infected by the weekend.
A doctor at a hospital treating the infected said that more than half of the people in the hospital were infected with the new, deadly strain.
The World Health Organization said on Monday that the new strains of the coronavirus were also found in other countries, including Malaysia and Japan.
The WHO said it was not aware of any cases of the new coronaviruses in the United States.
It said on Wednesday that it had tested blood samples of a person in Texas from the same outbreak, and said the results did not show any traces of the virus.