The new virus could mutate and spread further, Chinese health officials have warned, as they step up containment measures.
The death toll has risen to nine with 440 confirmed cases, they said.
A National Health Commission official admitted that the country was now at the “most critical stage” of prevention and control.
On Tuesday, authorities confirmed that human-to-human transmission of the virus had taken place.
In one of the first public briefings since the beginning of the outbreak, National Health Commission vice-minister Li Bin said there was evidence that the disease was “mainly transmitted through the respiratory tract”.
But China has still not been able to confirm the exact source of the virus.
“Though the transmission route of the virus is yet to be fully understood, there is a possibility of virus mutation and a risk of further spread of the epidemic,” said Mr Li.
The warning comes as millions of people across China are travelling within the country for the Lunar New Year week-long holiday. Thousands are also travelling abroad.
-BBC
