Villages in Vietnam with 10,000 people close to the nation's capital were placed under quarantine on Thursday after six cases of the deadly new coronavirus were discovered there, authorities said.
The locking down of the commune of Son Loi, about 40 kilometres (25 miles) from Hanoi, is the first mass quarantine outside of China since the virus emerged from a central Chinese city late last year.
"As of 13 February 2020, we will urgently implement the task of isolation and quarantine of the epidemic area in Son Loi commune," said a health ministry statement.
"The timeline... is for 20 days".
Son Loi is a farming region made up of several villages.
The health ministry previously said five people in Son Loi had been infected with the virus, and on Thursday reported a sixth case.
On Thursday, checkpoints were set up around the commune, according to AFP reporters in Binh Xuyen, a district on the outskirts of Son Loi.
Health officials wearing protective suits sprayed disinfectant on vehicles by the checkpoints.
Villager Tran Van Minh told AFP that authorities had already advised residents to avoid large gatherings.
"Life has been badly affected," he told AFP by phone, adding that much of the labour force is reliant on jobs in construction and house painting.
"Now we cannot get out and even if we do, clients don't welcome us that much as before."
More than 1,350 people have died in China from the virus, and nearly 60,000 others have been infected, since it was first detected in the Hubei province in early January.
China has imposed unprecedented quarantines across Hubei, locking in about 56 million people, in a bid to stop it spreading.
Tens of millions of others cities far from the epicentre are also enduring travel restrictions.
The virus has also had massive ramifications globally, with many countries banning travellers from China in a bid to stop people spreading the disease.
Vietnam, which shares a porous border with China, has 16 confirmed cases of the coronavirus, including those in Son Loi.
Vietnam had banned all flights to and from mainland China in a bid to stop the virus from spreading.
It also suspended new tourist visas for Chinese nationals or foreigners who had been in China over the past two weeks.