An 11-year-old Mexican boy who lives in a northern city plagued by drug violence and shootouts has designed a bullet-proof backpack with a GPS tracker and an alarm system.

Juan David Hernandez, who lives in Matamoros on the border with the United States, presented his special school gear at a science fair in the state of Tamaulipas, according to local media.

The bag, which has the words "security backpack" inscribed on the back, weighs five kilograms (11 pounds).

It includes a steel plate to stop projectiles, an emergency alarm, a GPS locator, reflecting lights and a cellphone charger.

"You never know when a stray bullet can hit you or when you can be in the middle of crossfire, which is why I focused on designing something that could protect me and other students from so many shootings," Hernandez told El Universal newspaper.

He said students in his class have had to drop on the floor as shootouts broke out outside his school.

Hernandez estimates the bag could cost between $48-$72.