A pair of toddlers who were left at home alone so their mother could collect a pizza killed their baby sister after they put her in an oven and turned it on.

J'Zyra Thompson was found with severe burns at a house in Houston, Texas, in the United States.

Their mother, seven-month pregnant Racquel Thompson, tried to resuscitate the 19-month-old but failed to and she died at the scene.

She had left her four children - all under the age of five - at home while she and her boyfriend went to Domino's Pizza and a Walgreens pharmacy to pick up a prescription, police said.

One of the two three-year-olds involved told Child Protective Services (CPS) they put J'Zyra in the oven and the other "made it hot".

The baby was kicking the oven door while inside, court records stated.

Case workers say the couple left the four kids at home last Thursday without telling a grandmother who lived in the same apartment complex.

No charges have been filed against Thompson or her boyfriend but criminal charges are expected, CPS workers said.

Thompson's ex-boyfriend, Fredrick Price, came looking for his two three-year-old children on the morning of the incident, saying he had not heard from his children in months and had been trying to contact Racquel.

He said: "She was a cute little baby, I just didn't know if that was my daughter or not.

"It's very irresponsible, someone should have been here or I should have gotten a phone call, come and get my children."

Mr Price added he had never taken a paternity test to see if he was the father of his ex-girlfriend's youngest child.

The remaining three children have been placed in foster care as it was deemed there were no suitable relatives to take care of them.

Thompson also has an older child who lives with his father and allegedly drove her children around without a licence or child car seats.