Over 30 police officers and militia members placed barricades and checkpoints around Road No.10 in Hiep Binh Chanh Ward to prevent people from getting in and out of the area.
Five medical workers in protective suits entered several houses to disinfect them. Around 40 families in the area were requested to stay inside.
"This might only be a suspected infection case, but the lockdown and disinfection are required to be safe," said a representative of the Thu Duc District Medical Center, adding that the person had returned from Da Nang City, now Vietnam's largest Covid-19 hotspot.
The suspected case is a woman who had been treated in Da Nang's Da Nang Hospital before being transferred to Saigon. She was quarantined Tuesday. Her Covid-19 test results are awaited.
As of Thursday night, Saigon had two confirmed active cases: a 57-year-old American martial artist and his 46-year-old Vietnamese wife who’d also come to Saigon from Da Nang. Following their confirmation, the Cho Ray Hospital and a residential area in Ward 16 in District 8 were placed under lockdown.
The two cases, confirmed Wednesday, ended Saigon's 117-day streak of no community transmission of the novel coronavirus.
The southern metropolis will shut down all its bars and dance clubs and ban large gatherings starting Friday.
Vietnam has recorded 464 Covid-19 cases so far, of which 95 are active. The country recorded 14 new cases Thursday: eight in Da Nang, one in Hanoi and five in Quang Nam.
All of Saigon’s 61 previous cases were discharged after recovery.