The number of new Korean cases reported on Tuesday was a sharp drop from 23 on Monday but the number of schools closed grew to 2,199, including 19 universities. Hong Kong's secretary for administration, Carrie Lam, told reporters just ahead of a meeting of the city's Executive Council that the red alert would be issued. A red alert is defined as a "significant threat" according to the Hong Kong government, and means people should "adjust travel plans" and "avoid non-essential travel" On Monday, Hong Kong upgraded its response to the outbreak in South Korea to "serious".
Nam Kyung-pil, governor of Gyeonggi province, which surrounds the South Korean capital, Seoul, said the country was fighting two wars. "The war against the disease and the war against fear," he said.
The World Health Organisation began work on a joint mission with South Korean doctors and officials to review the country's response and analyse the virus.
The WHO has not recommended any curb on travel, but thousands of tourists have cancelled plans to visit South Korea.