Most of the new cases were detected in Hanoi, at 1,766.
It was followed by Tay Ninh Province with 938 cases and Vinh Long Province with 917 cases. Both localities are in the south.
In the past 24 hours, 245 Covid-19 patients have died, including 40 in HCMC.
Since the pandemic started last year, the death toll in Vietnam has climbed to 31,877 or 1.9 percent of all infections.
In the latest wave that hit the country in late April, more than 1.68 million cases have been confirmed and nearly 1.3 million of them have recovered.
So far, 69.8 percent of the population have received two vaccine doses.