The new clusters were identified after people visited local hospitals to have their health checked.

Contact tracing uncovered new clusters unrelated to previous ones, Nguyen Tan Binh, director of the municipal Health Department, told a meeting Friday as the city undergoes 12 days of social distancing.

Of the four new clusters, the one related to a residential area in Cu Chi District, a mechanic factory in Hoc Mon District, and a hotel in Tan Binh District, has so far recorded 31 cases after six people sought medical checks at three different hospitals Tuesday.

All six had visited the factory in Cu Chi and from them, the virus spread to 25 others who are either family members or neighbors.

The cluster at the Ehome residential building in Binh Tan District has reported at least 16 cases. It was detected after two residents had their medical checkups at the City International Hospital on June 5 and Trieu An Hospital two days later.

From them, 14 more people have contracted the virus, including a woman working at footwear maker Pouyuen Vietnam, the biggest employer in HCMC with 65,000 staff, prompting the company to suspend as many as 1,100 employees Thursday.

The cluster at a residential area in Hiep Binh Phuoc Ward of Thu Duc City has registered six cases after a person visited Duc Khang Hospital on June 2. Five people who either live in the same house or work with the person all got infected.

The remaining cluster is in another residential area in Tan Thoi 2 Ward of Hoc Mon District. It reported 10 cases by Friday after a person sought a medical examination at Hoc Mon Hospital on June 5. Nine others who live in the same house with the person or are neighbors were infected too.

According to local health officials, the clusters were identified as a social distancing order is applied across the city, and thus infections should not spread.

"It is possible sources have been silently infecting the community or that infected people have already had contact with Covid-19 cases or visited affected areas and failed to declare such information," said Binh.

Since May 26, the city has been dealing with its biggest Covid-19 cluster ever that emerged from Revival Ekklesia Mission, a Christian congregation based in Go Vap District. Until now, the transmission source of this cluster remains unknown and has been responsible for 441 cases across 21 out of 22 city districts.

On May 31, social distancing measures had been imposed across the city for at least 15 days in line with Directive 15, which requires suspension of social events, bans gatherings of 20 people or more in one place and of 10 people or more outside workplaces, schools and hospitals, and ensures a minimum distance of two meters between people in public.

However, Go Vap and District 12's Thanh Loc Ward must follow Directive 16, which is stricter as it does not allow gatherings of more than two people in public and asks people to only leave home for emergencies, buying food and medicine, and working in factories, production facilities and businesses that involve "essential" goods and services.

Authorities stated earlier this week they would consider ending or continuing these measures based on the actual situation.

On Friday, Go Vap chairman Nguyen Tri Dung proposed lifting the social distancing rule completely after 15 days if no new cases are detected in the community in the next few days.

He said he came up with the proposal because the district hotspot had been brought under control, with recent cases all recorded in isolated areas, and that both local people and businesses are facing certain difficulties under strict measures to contain Covid-19.

District 12’s chairman Le Truong Hai Hieu, meanwhile, suggested extending the social distancing order under Directive 15 after 15 days.

Ever since the fourth wave broke out in Vietnam in late April, HCMC has recorded 590 local cases, standing third in the number of infections among all infected localities after Bac Giang and Bac Ninh provinces.

The city currently hosts 9,833 in centralized quarantine camps for having direct contact with Covid-19 cases, and has 15,796 others self-quarantined at home or accommodation facilities