At least three employees of a multinational company that held a meeting of more than 100 international staff inSingapore have contracted the new coronavirus, sparking a World Health Organization investigation of the case.
Malaysia and South Korea have confirmed three cases of the virus related to the mid-January company meeting held with 94 overseas staff at the Grand Hyatt hotel, and Singapore said late on Wednesday four other attendees were showing symptoms.
Authorities have not revealed the name of the company that held the meeting or said what business it is involved in.
Malaysian health authorities have said people from China including one from the city of Wuhan, where the virus emerged in December, attended.
"WHO is coordinating with relevant ministries of health in relation to it," Olivia Lawe-Davies, a spokeswoman for the WHO, said in response to questions from Reuters.
"As countries are stepping up surveillance, the detection of more cases of local transmission can be expected."
Singapore has reported 28 cases of the coronavirus, including some involving person-to-person transmission.
The cases linked to the Singapore business meeting provide more evidence the virus is spreading through human-to-human contact outside China, which the WHO has said is deeply concerning and could signal a much larger outbreak.
China reported its biggest daily jump in fatalities from the virus on Thursday, up 73 to 563, although there have been only two reported deaths outside mainland China.
Malaysian health authorities first revealed the link to the Singapore business meeting when they confirmed the case of a 41-year-old Malaysian who had attended it, along with colleagues from China.
South Korea subsequently confirmed two cases involving South Korean who attended the conference. The Koreans and the Malaysian shared a buffet meal during the conference, South Korean media reported.
Of the 15 Singapore attendees, four have been referred to its National Centre for Infectious Diseases, Singapore's health ministry said. All the overseas attendees have left Singapore, the ministry added.
A spokesman for the Grand Hyatt, Gerald Kheng, said the hotel had been deep cleaned after it was first informed of the incident by the health ministry on Tuesday and it was not aware of any other cases among guests or staff.
The city-state says no evidence has emerged of widespread community spread but it announced new precautionary measures on Tuesday including halting group activities such as school assemblies.
Several firms in Singapore have suspended business and media events, including a big travel fair, but the Singapore Airshow is set to go ahead next week albeit on a smaller scale.