The fire began in the three-story building on Hang Luoc Street in the downtown district at around 4:40 a.m. There were five people inside at the time: the two owners and three of their relatives.
The flames engulfed the small house quickly and there were explosions.
One of the five insides, a daughter of the owners, 36, managed to escape to a neighbor's balcony.
Seven fire trucks and 39 officers arrived at the scene. The men had to break through the doors on all three floors to douse the flames.
They brought the fire under control at around 5:07 a.m.
But inside they found four people had died of suffocation: the owners and two children aged seven and 10.