Chinese government experts have confirmed human-to-human transmission in an outbreak of a new coronavirus.
State media cited the National Health Commission as saying two people caught the virus from family members and some health workers had tested positive.
The outbreak initially was connected to a seafood market in the central city of Wuhan, but human-to-human transmission could make the virus spread more quickly and widely. News of the illness spreading among people came as China reported a sharp uptick in cases.
Six people have died and 291 have been infected in China.
Face masks are selling out and temperature checks at airports are the new norm as China tries to control the outbreak that has reached four other countries and territories and threatens to spread further during the Lunar New Year travel rush.
The stock prices of some companies that sell masks have risen, but markets fell in much of Asia as investors worried about the potential impact on tourism and the economy. That prompted a selloff of airlines and other travel businesses.