Black Friday, the day with the biggest sales in the year because of the bargains offered by retailers, lost some of its luster when a woman unleashed pepper spray on other shoppers at a Walmart in Los Angeles, leaving some 20 people injured.

A woman desperate to get the best offers in electronic devices pepper-sprayed people waiting to make their purchases in order to drive them away from the merchandise she coveted, the Los Angeles Times said.

At least 20 shoppers were injured including children, according to police who are still looking for the woman who attacked the other customers.

Witnesses described the frenetic scene where customers tore down video-game displays, trampled posters and pushed and shoved each other to get the best product discounts.

"People started screaming, pulling and pushing each other, and then the whole area filled up with pepper spray," shopper Alejandra Seminario said.

Despite the chaos, the store stayed open and those unhurt by the pepper spray went on with their bargain-hunting.

"I don't care. I'm still getting my TV," said 20-year-old Nakeasha Contreras, who arrived at the store around midnight, two hours after the pepper-spray incident.