Hanoi recorded 2,723 cases, followed by Hai Phong with 795 and Khanh Hoa with 790.
The death toll since the pandemic started has risen to 33,877 after 233 deaths were announced in the past 24 hours.
In the latest wave that hit the country in late April, more than 1.85 million cases have been confirmed and 1.47 million of them have recovered.
So far, more than 70.5 million people have been fully vaccinated.