NEW YORK – The mobile payment wars are heating up.

Wal-Mart Stores Inc., the world’s largest retailer, said it’s launching its own mobile payment system that will allow shoppers to pay with any major credit or debit card or its own store gift card through its existing smartphone app at the cash register.

It started testing the new payment feature Thursday at its stores in the Bentonville, Arkansas area, where the retailer is based. It plans to launch the payment system called Walmart Pay in all 4,500-plus U.S. stores in early next year.

It’s part of Wal-Mart’s overall mobile strategy to making shopping easier and faster, but the launch is the latest salvo in the battle for mobile payments that’s in the early stages. Wal-Mart has moved into the field as Apple’s one-year-old tap-and-pay system is being expanded to other merchants like Best Buy and KFC and several months after Google launched the Android Pay mobile wallet app and Samsung came out with Samsung Pay. They’re all trying to get a piece of what could be a very lucrative business, but none of them have cracked the market so far. The move signals that Walmart believes it’s best to build its own system to better serve its customers, even as it backs a retail industrywide mobile payment program that is in test phase. “We are creating a seamless shopping experience that includes payment,” Neil Ashe, president and CEO of Wal-Mart’s global eCommerce, told reporters on a conference call on Wednesday.