Cameras at Walmart’s self-checkout counters and vigilant employees armed with handhelds have led to some tense encounters with shoppers, Business Insider reports.

With shoplifting spiking across the country to such a degree that big-box chains like Target are closing stores in major cities, Walmart's push to get ahead of the theft has, at best, made customers confused or uncomfortable.

At worst, it’s made several mad — so mad that a couple of shoppers have hurled merchandise at Walmart employees.

If cameras at a self-checkout register sense that a customer has not scanned all of their items for purchase, it locks up the register and plays back the video showing the items the customer has scanned. Walmart employees nearby are alerted via handhelds or mobile phones to approach the customer.

The problem, seven former and current employees told Insider, is that Walmart employees are prohibited from accusing any customer of theft. They’re also not being given enough training on how to handle various situations, according to the sources.

Walmart employees have been coached to blame the machine on the errors, not the customer, and to guide shoppers to checkout lanes equipped with cashiers.

“The policy is to take the item away from them and tell them something like, ‘Oh, I think the machine didn’t scan it,’” said one Walmart employee. “And if they don’t want it, then we take it away.”

If an employee suspects someone is outright stealing, they must alert a store manager, who will in turn notify store security.

The new technology “feels more confrontational than it was before because it’s right there—the evidence is right there,” said one employee.

The experience of a register locking up catches most customers off guard, another worker said.

Walmart employees aren’t enjoying the new self-checkout, either. Dominick Haar, a 20-year-old recently hired at a Walmart in southern Illinois, said, “It was personally uncomfortable for me to notice somebody purposefully not scanning an item. I just personally felt weird going up and trying to find the right words to put together.”

Another Walmart worker, speaking on condition of anonymity, agreed: “It’s really uncomfortable, and it becomes, like, a safety issue.”

Another: “Mostly those who are trying to scam the register are the ones who get upset the most.”

Last month, Target announced it is closing nine stores in major cities including New York, Chicago and San Francisco due to rampant theft and concerns over employee safety.

Walmart also closed stores this year, including its last two in Portland, without admitting the closures were due to pilfering. However, Walmart CEO Doug McMillion earlier this year called out theft as “higher than what it has historically been.”

Last month, a Walmart in Atlanta was set on fire by arsonists. Walmart plans to reopen the store with a new police “workstation” inside, the company said.

Walmart spokesperson Joe Pennington said in a statement to Insider, “As with other retailers, theft is always a challenge, and we’re always looking for better ways to tackle this issue.”