Two more children have died and their mother remains under police guard following a suspicious house fire in Toowoomba, Queensland.

Seven people — a 34-year-old man, a 36-year-old woman and five children — were inside a home in Harristown when it was engulfed in flames about 12.30am yesterday.

The adults and four of the children managed to escape. 

When the fire was extinguished, the body believed to be of a nine-year-old boy was found inside. 

Two more children, girls aged four and seven, were hospitalised with critical injuries sustained in the fire and died last night.

The 34-year-old man and the other two children — an 11-year-old boy and an 18-year-old man — were also hospitalised but have since been discharged.

The 36-year-old woman remains in a critical condition in the Royal Brisbane and Women’s Hospital.

She is under police guard and has not been questioned yet.

Queensland Police’s George Marchesini confirmed the woman was the mother to all of the children while the man is the father to some of the children. 

Marchesini also said police had visited the home and spoken with the family in the past.

The house remains a crime scene and police are treating the fire as suspicious.

Investigations are ongoing and police are speaking with extended family members living interstate.

They are not looking for anybody else in connection with the incident.

In the meantime, bouquets are growing outside the home as community members come to terms with the incident.

“It breaks your heart. I just feel for everyone involved, I’m hoping that they can recover,” local Chloe Nutt told 9News.

Premier David Crisafulli also acknowledged the loss today.

“A little bit of the soul of a really tight-knit community will be feeling removed today,” Crisafulli said.