The world has entered uncharted territory in its battle against the deadly coronavirus, the UN health agency warned, as new infections dropped dramatically in China but surged abroad with the US death toll rising to six.

Globally, the virus has killed more than 3,100 people and infected over 90,000 even as a clear shift in the crisis emerges, with nine times as many cases recorded outside China as inside, according to the World Health Organization.

"We have never before seen a respiratory pathogen that is capable of community transmission, but which can also be contained with the right measures" — WHO chief Tedros Adhanom Ghebreyesus

Community transmission means infections within a population are not imported from another virus-hit area.