The tourists, including over 50 foreigners, had their samples taken for testing on August 9, as requested by the HCMC Health Department. They were tested once.

The Center for Disease Control and Prevention (CDC) in central Da Nang City, Vietnam's Covid-19 epicenter, has since confirmed all as negative and ready to return to HCMC on three flights departing 3 p.m. Thursday, and 9 a.m. and 2 p.m. Friday.

Doctor Nguyen Ngoc Thuy Duong, from the HCMC CDC, told VTV once they touched down at Tan Son Nhat Airport, all passengers would be taken to quarantine camps as per regulations imposed on those returning from Covid-19 stricken areas.

HCMC residents will be isolated inside the city while those from nearby regions will be escorted by military personnel to facilities in their hometowns for quarantine, she said.

City Chairman Nguyen Thanh Phong announced Monday that from August 14, all those returning to HCMC from Da Nang between July 1 to 28 and failing to report themselves to authorities would face criminal charges.

Nearly 1,700 visitors, mainly from HCMC and Hanoi, remain stuck in Da Nang.

Four flights will carry 828 people to Hanoi on August 12 and 13, including 29 foreigners.

Hanoi, however, did not request Da Nang to test any returnees beforehand.

Once arriving at Noi Bai International Airport, they will be sent to a military facility for 14-day quarantine, during which they will be tested for the virus.

Da Nang imposed 15-day social distancing measures on July 28 and has extended them for another two weeks from Wednesday. Public transport, including flights to and from the city of 1.1 million, is suspended during the periods.

The move came as locally transmitted cases reemerged in Vietnam on July 25 after more than three clean months.

Da Nang has since reported 283 domestic infections. The disease has spread to 14 other cities and provinces, including HCMC and Hanoi.

So far, 17 patients have died.