A three-year-old girl shot her pregnant mother after finding her father’s loaded gun, police said.

Shanique Thomas was sitting in the front seat of the car outside shops in Merrillville, Indiana, a small town around 40 miles south of Chicago, when she was shot between the chest and shoulder, according to the Lake County Sheriff’s Department.

“There was blood flowing all from her stomach – just coming out like water, like a faucet,” said Hadassah Zirkle, who was working in a shop nearby when someone walked in and told her a woman was bleeding outside.

She told NBC Chicago that she took the children inside the store so they could not see their injured mother.

The toddler “had no idea what she had done and she was very scared”, Detective Sergeant James Bogner said.

Ms Thomas was rushed to a local hospital before being transferred to a hospital in Chicago, where she remains in a critical but stable condition.

Local media reported that the 21-year-old was believed to be around six-weeks pregnant. Her one-year-old son was also in the car at the time.

Ms Thomas’s partner Menzo Brazien, was inside a shop at the time of the shooting. He told police he left the weapon by the side of his seat. Police arrested him on suspicion of child endangerment.

“It’s frustrating. It was an unfortunate, careless incident that should’ve been prevented and it should’ve never happened,” Merrillville police chief Joseph Petruch told The Chicago Tribune. “Now this three-year-old, she’s going to have to live with this.”

Police said the family live in Michigan City and the children had been placed in protective custody.