US boy hailed a hero after breaking into car to save trapped toddler

Nikki Fields and her son Ben Theriot were at a shopping centre in Tulsa, Oklahoma on Monday - the hottest hottest day of the year so far in the city.

So, when the 12-year-old boy saw a toddler in a locked car, crying on the 47C day, he knew he had to act quickly.

Describing the incident, Ben says he first tried to smash the driver's window with a ratchet strap but when that didn't work, he went for the windscreen.

"I thought it would be a lot easier because it's bigger," he told Fox News 23.

Re-enacting the rescue, the 12-year-old added: "I swung it over my shoulder and hit it right there."

Eventually, Ben was able to crawl inside the car and get the two-year-old boy out from the vehicle.

The toddler was red faced and distressed but otherwise OK.

The mother was found shopping inside the mall's discount department store Ross Stores and told authorities it was an accident.

Police fined the mother $250 (AU$368) under the state's Forget-Me-Not laws but did not arrest her for child neglect.

While to toddler remains with his mother at the moment, there has been a Department of Human Services investigation launched into the matter.