Only buses transporting workers and taxis are allowed to operate but with stringent prevention measures like filling up only half their seats, ensuring everyone on board wears a masks and keeps a distance from others, keeping their windows open and turning off air conditioners.

Ever since the disease first broke out health experts have been telling the public to keep places airy and warm to debilitate the virus.

Chi Linh and Kinh Mon towns and Nam Sach and Kim Thanh districts are off-limits even to taxis because of their high number of infections.

Hai Duong has closed its borders to all vehicles, including those carrying cargo and private vehicles, except those permitted by authorities.

Since community transmission reemerged on Thursday after a break of 55 days, Hai Duong has recorded 157 cases, including 32 on Saturday morning. Neighboring Quang Ninh has reported 20 cases.

Chi Linh Town, where the first case was detected, a woman working for Vietnam Poyun Electronics Co. Ltd, has become the biggest cluster. The town of 220,000 residents has been locked down for 21 days starting at noon on Thursday.