Hoang Quoc Hung, director of the Lao Cai Health Department, said the northern border provinces saw a sudden increase in migrant workers returning home Wednesday morning from China.

Local authorities decided to open a separate quarantine camp at the Thai Nguyen University Campus, which has a maximum capacity of 1,600 beds, to accommodate current and future returning workers.

"The province has welcomed about 500 workers coming back from China over the past three days. The reason for their return is the impact of the Covid-19 pandemic which has forced Chinese factories to lay off workers," he said.

Hung said nearly 200 people working on farms across the border returned home by trails and open paths, from where border guards found them and took them to the quarantine zone.

"We have already tested them and have not detected any infection cases yet."

The province expects to welcome about 2,900 more workers in days to come, Hung said.

Since the beginning of the Covid-19 outbreak, Lao Cai has established nine quarantine camps across eight border districts and one in the provincial center. As of April 18, the province had opened four more camps in Bac Ha, Si Ma Cai, Muong Khuong and Bat Xat districts.

Vietnam has spent a week without a new Covid-19 infection, keeping its tally unchanged at 268 since last Thursday.

With 223 patients discharged, the number of active cases stands at 45, the Health Ministry confirmed.

The Covid-19 pandemic, now in 210 countries and territories, has a reported death toll of more than 183,800.