The World Health Organisation on Monday said the global risk from the deadly virus in China was "high", admitting an error in its previous reports that said it was "moderate".
The UN health body said in a situation report published late on Sunday that the risk was "very high in China, high at the regional level and high at the global level".
In a footnote, the WHO said there had been an "error" in previous communications published on Thursday, Friday and Saturday which "incorrectly" said the global risk was "moderate".
Asked for more detail, WHO spokeswoman Fadela Chaib said only that it was "an error in the wording".
The WHO on Thursday stopped short of declaring the virus an international public health emergency -- a rare designation used only for the most severe outbreaks that could trigger more concerted international action.
WHO chief Tedros Adhanom Ghebreyesus, who is visiting China this week to discuss further action to contain the virus, on Thursday said: "This is an emergency in China, but it has not yet become a global health emergency".
WHO's cautious approach can be seen in the context of past criticism over its slow or too hasty use of the term, first used for the deadly 2009 H1N1 swine flu pandemic.
During that outbreak, the UN health agency was criticised for sparking panic-buying of vaccines with its announcement that year that the outbreak had reached pandemic proportions, and then anger when it turned out the virus was not nearly as dangerous as first thought.
But then in 2014, the WHO met harsh criticism for dragging its feet and downplaying the severity of the Ebola epidemic that ravaged three west Africa countries, claiming more than 11,300 lives by the time it ended in 2016.