Government staff members register persons subject to compulsory testing in Tai Hing Estate, Tuen Mun on Feb 5, 2022. (PHOTO / HKSAR GOVERNMENT)

HONG KONG - Twenty-six preliminary COVID-19 cases were detected during overnight targeted testing operations in Sha Tin and Tuen Mun.

In a statement issued at noon on Sunday, the government said 13 preliminary cases were found at Sun Yuet House and Sun Wai House, Sun Chui Estate, Sha Tin after 3,871 residents were tested for the coronavirus.

The government said 13 preliminary cases were found at Sun Yuet House and Sun Wai House, Sun Chui Estate, Sha Tin after 3,871 residents were tested for the coronavirus

Eleven preliminary cases involving four households were found in Sun Yuet House while two preliminary cases in two households were detected in Sun Wai House.

The buildings were cordoned off at 7 pm on Saturday after sewage samples tested positive for COVID-19, leading to concerns that there might be asymptomatic cases in the area.    

At the same time, the government also cordoned off Hing Cheung House, 6 Tai Hing Street and Hing Tai House, 2 Tai Hing Street, in  Tai Hing Estate, Tuen Mun due to positive sewage samples. 

The government said two preliminary cases were found at Hing Cheung House while 11 preliminary cases and one indeterminate case were detected at Hing Tai House.

“In view of the significant risk of infection at Hing Tai House, Tai Hing Estate, we consider it necessary to undertake determined action by extending the 'restriction-testing declaration' operation made earlier..to February 7 to prevent the virus from further spreading," a government spokesman said.

Government staff members visited 1,332 households in Hing Cheung House but 151 did not answer the door. The government said it will take follow-up measures to ensure that they are also tested.

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In a separate statement, the Customs and Excise Department said a customs officer at the Hong Kong International Airport tested preliminarily positive for the virus on Saturday night. 

He had a meal with his friend after his last working day on Feb 1 and his friend later tested positive for COVID-19. 

The officer, who performed baggage inspection duties at the Apron, has no travel history in the past 14 days and was wearing surgical masks while at work. He is now in stable condition.

READ MORE: 23 positive virus cases found in 5 testing operations

All frontline customs officers at the airport have been undergoing COVID-19 testing once every two days. Until now, test results of the other officers have been negative, the department said.