The ceremony began at 5 am at Quan Su Pagoda, the headquarters of the Vietnam Buddhist Sangha, and was followed by Buddhist chanting and prayers for fallen soldiers, as well as prayers for peace and national prosperity.
Venerable Thich Duc Thien, vice chairman and secretary-general of the Sangha's Executive Council, said July is a time for people across Vietnam to remember and honour those who sacrificed their lives for the country.
He said the ceremony reflects the Buddhist tradition of gratitude and remembrance, particularly for those who gave their lives for Vietnam's independence and peace.
This year's observance also coincides with the government's 500-day campaign to search for, recover and identify the remains of fallen soldiers.
Ahead of the anniversary, the Vietnam Buddhist Sangha called on its branches and affiliated organisations to hold memorial ceremonies nationwide, including the simultaneous ringing of three rounds of Bat Nha bells and drums at 5 a.m. on July 27.
The Bat Nha bell and drum ceremony is one of the most solemn rituals in Vietnamese Buddhism and is traditionally performed before major religious festivals and ceremonies.