Amazon on Thursday opened its supermarket in Los Angeles with shopping carts that let customers skip checkout lines, as the e-commerce company builds out its offline presence, Reuters reports.

The market, in the Woodland Hills neighborhood, is called the Amazon Fresh grocery store.

It is the first location to let customers in - by invitation only - out of seven that Amazon has confirmed for Southern California and greater Chicago. The Woodland Hills site will open to the wider public in coming weeks, Amazon said.

Customers can enter the store the traditional way, but if they want to use the cart, they need to open up their Amazon app and swipe it, USA Today reports.

Jeff Helbling, Amazon's vice-president of the Fresh Stores, says the shopping cart uses "a combination of computer vision algorithms and sensor fusion," within the cart to identify and tally up the items.

The world’s largest online retailer has experimented with physical stores in recent years to capture more consumer spending, particularly in groceries.

It has more than 20 cashier-less shops with grab-and-go food for office workers and over 500 stores in the Whole Foods Market chain it acquired in 2017.

Amazon’s latest concept faces stiff competition from far larger incumbents Kroger Co and Albertsons Companies Inc.

It is roughly the size of a Whole Foods store at 35,000 square feet (3,252 square meters) but serves a different need, not focused on natural and organic items, said Amazon Vice President Jeff Helbling.

“We feature a lot of national brands,” he told Reuters. Prices are “lower than the other options that the people have in the Woodland Hills area.”

Earlier this year, Amazon said it would start selling the technology behind its cashierless Amazon Go stores to rival retailers.

It also said it was adding more capacity to its online grocery delivery business.