Hong Kong reported four more Covid-19 cases on Sunday, with all the latest patients having travelled outside of Hong Kong recently.
Health authorities said in order to further prevent the spread of the virus, the government may impose travel restrictions on visitors from Britain and the United States.
A 35-year-old man who lives in Fanling recently went to Hokkaido, Japan, for a ski trip. He started coughing on Wednesday and was being treated in hospital.
A 29-year-old non-Chinese man flew to Germany earlier this month, from where he drove to Austria. He later returned to Hong Kong from Frankfurt and has since tested positive.
Two other men, aged 37 and 39, are friends who visited France recently. Both are ethnic French and live in Hong Kong.
Health authorities say they're all imported cases, and the total number of confirmed cases in Hong Kong has risen to 145.
And according to preliminary results, a non-Chinese couple who live on the Peak have tested positive for the coronavirus. The 58-year-old man and 61-year-old woman recently visited Toronto, New York and Boston.
"We have many, many imported cases and possible imported cases recently. It's quite difficult to control (the situation) because we're not sure if we have caught all the imported cases, or there may be some that go unnoticed or not detected. So, that may cause a further spread in the community," Dr Chuang Shuk-kwan of the Centre for Health Protection said.
"So, we're trying to enhance our surveillance system to try to catch all the cases."
Dr Chuang said travel is a high-risk activity. She also noted cases in which people failed to declare upon arrival here that they had not been feeling ill while still outside of Hong Kong. Dr Chuang said those found guilty of not coming clean on their health declaration forms could be jailed or fined.
As for the partial evacuation of a Tai Po public housing block where three confirmed coronavirus patients live, Dr Chuang said they have so far failed to contact one family in question. Authorities were evacuating 12 families: units 13 and 14 from the 29th to 34th floors of Heng Tai House at Fu Heng Estate.
Eight other flats at floors below have also been cleared. A total of 43 residents were evacuated.
Professor Yuen Kwok-yung from the University of Hong Kong said it's likely that a plumbing air vent pipe - which removes gases and odours - near the roof, may be spreading the virus.
Last updated: 2020-3-15 HKT 20:35
Concern grows about imported Covid-19 cases
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