Thirty-one local infections of COVID-19 and two deaths were registered in Vietnam on Sunday, according to the Ministry of Health.
Sixteen of the new patients were recorded in Da Nang, a coastal city and a national outbreak epicenter at the moment.
Three virus-related fatalities were announced the same day, two women in their eighties and one 53-year-old woman who all had suffered several underlying medical problems.
The health ministry also confirmed three imported cases on Sunday, two Vietnamese returnees from Russia and one overseas Vietnamese student from the U.S.
Vietnam has detected 620 imported and local COVID-19 infections as of Sunday evening, with six deaths who were old and had pre-existing conditions.
New community-based cases have been logged in Da Nang, Quang Nam Province, Ho Chi Minh City, Hanoi, Quang Ngai Province, Thai Binh Province, Dak Lak Province, Dong Nai Province, and Ha Nam Province since last month.
A total of 173 locally-transmitted cases have been traced to Da Nang since July 25, after 99 days of no documented community transmission of the virus in the Southeast Asian nation.
Vietnam is quarantining 94,216 people who were in close contact with infected patients or entered the country from outbreak-stricken regions at the time of writing.
The country has closed its borders to foreigners since March to prevent COVID-19 spread.
However, foreign experts and skilled workers have been allowed to make an entry, subject to government approval and mandatory quarantine.
The national government has also sent aircraft to bring back citizens stranded in other countries over the health crisis.