Vietnam registered 11 new community cases of the coronavirus in the central city of Danang Monday evening, VN Express has reported.
The new patients, which include four medical staff, have taken the national tally to 431 cases, with 15 recorded in the last three days.
The youngest new patient was 17 and the eldest 71-years old. Seven are being treated in Da Nang Hospital C, as well as the four medical staff.
On Saturday, Vietnam ended 99-consecutive days without a single locally-transmitted case of the coronavirus, and there have been 15 cases since.
Danang started 14 days of social distancing measures on Tuesday, which will also see the closure of non-essential services such as massage parlors, KTVs and bars, the report said.
The country has also restored pandemic prevention measures such as restrictions on public transport, including planes, trains, boats and buses.
All transport services have been ordered to reintroduce hand sanitizer and ensure that staff use masks and conduct temperature tests on passengers, as per Ministry of Transport orders.
Long-distance travelers must now also complete administrative procedures, which were first originally introduced in March.
From mid-April, Vietnam went 99-days without any domestic transmission of Covid-19, with the new outbreak causing widespread worry across the country.
The coronavirus has infected over 16 million people worldwide in over 200 countries and regions, killing over 650,000.
Vietnam has not recorded a single death from the coronavirus so far.