HONG KONG, Jan. 25 (Xinhua) -- Hong Kong has reported three more cases of pneumonia caused by the novel coronavirus, bringing the total number of confirmed cases here to five.

Respiratory samples of three travelers from Wuhan were tested positive for novel coronavirus. The patients, in stable condition, were under isolation in hospital, according to the Center for Health Protection (CHP) of the Department of Health of the Hong Kong Special Administrative Region (HKSAR) government.

Of the three new cases, the first involved a 62-year-old woman, who arrived in Hong Kong by train on Jan. 19 and developed fever and cough on Jan. 20.

Three of her family members, coming to Hong Kong with her, will be transferred to Lady MacLehose Holiday Village for quarantine although showing no symptoms.

The other two cases involved a couple from Wuhan, 62 and 63 respectively, who came to Hong Kong on Jan. 22 and presented symptoms over following days. Their daughter, also developing fever, will be under isolation, and their asymptomatic domestic helper will be under quarantine.

The CHP is making epidemiological investigations and relevant contact tracing of the five confirmed cases in Hong Kong.

Virus transmission chains of the five cases confirmed have been traced, Chuang Shuk-kwan, head of Communicable Disease Branch of the CHP, told a press conference on Saturday.

Chung Kin-lai, director of Quality and Safety Division of the Hospital Authority, said the five patients were largely in stable condition in Princess Margaret Hospital but stressed that the condition of one of the patients worsened on Saturday morning, who has started to use the oxygen concentrator to assist breathing.

As of Friday noon, the CHP has received reports of 239 suspected cases and 5 confirmed cases since Dec. 31, 2019, with 122 cases discharged already after being ruled out as novel coronavirus infection.

There has been a rising trend in the number of confirmed cases, Chuang said, stressing that the initial symptoms of patients infected with new coronavirus are not obvious, making it difficult to detect those cases early.

HKSAR Chief Executive Carrie Lam said on Saturday morning at the Hong Kong airport after coming back from the annual meeting of the World Economic Forum in Davos that the health of the public is the first priority. She added that a high-level meeting on the pneumonia situation will be held later Saturday.

The HKSAR government has activated the serious response level in its contingency plan to prevent the spread of the infectious disease. It has enhanced the monitoring of suspected cases, imposed a health declaration form system on inbound travelers by air and railway, and canceled festive events for the Lunar New Year celebrations.

Chinese health authorities said on Saturday that 1,287 confirmed cases of pneumonia caused by the novel coronavirus had been reported by the end of Friday. The pneumonia situation had resulted in 41 deaths.

To curb the spread of the epidemic, China on Thursday morning locked down central China's Wuhan city, the center of the novel coronavirus outbreak, and is mobilizing medical staff and resources nationwide to aid the city and control the epidemic.