Police in Thanh Khe District reported that the incident occurred at 1.30 am at a three-storey house on Tran Cao Van Street.
"The fire started on the ground floor and three people, a couple and their nine-year-old son managed to run out the door," the report said. "They tried to put out the fire and called for help. Some neighbours came to help them but failed to control the fire which was spreading fast."
When firefighters arrived, they faced difficulties getting their engines to the fire as the house lay in a small valley. When the fire was controlled at 3 am, two boys aged 14 and 12 were found dead in their bedroom on the second floor.
The house is heavily damaged.
Some witnesses said that the boys might have slept and did not notice the fire and they died from smoke inhalation from the fire.
Police are investigating the cause of the fire.