CHIANG MAI: A couple and their two-year-old son were burned to death, with the mother still hugging their child, when a fierce fire swept through their house shortly before dawn on Tuesday.

Seven fire trucks and crews battled the blaze at the two-storey house at Patan housing estate, Chang Phuek district,  the deputy chief of Chiang Mai police said.

The flames spread quickly and had already engulfed the house, made of wood and concrete, when they arrived.

Neighbours said people were trapped in a bedroom on the second floor. The intensity of the flames kept rescuers at bay. Fire crews raced against time to douse the fire and prevent it spreading to nearby houses, but it took them more than two hours to bring the blaze under control. 

When they entered the charred remains of the house they found the three members of the family dead in the second-floor bedroom. The mother, identified as Panida Thongkham, 28, was still hugging her two-year-old son Nawaphol. The burned body of her husband, Bundit Thongkham, 29, was nearby, Thai media reported.

Damrong Thongkham, 61, owner of the house and Bundit's father, said he slept on the first floor. His son and his family were on the second floor. He said he awoke to the smell of something burning and went upstairs to wake the couple, but there was no response to his knocking. 

Then he looked back downstairs and saw flames spreading quickly through the house. He ran outside and neighbours called the fire service.

Police suspect the fire was caused by an electrical short circuit. They were investigating.