It's also asking shoppers to no longer openly carry firearms in stores, in states where "open carry" is allowed, unless they are authorized law enforcement officers.

CEO Doug McMillon announces the changes following two deadly shootings at Walmart stores over the summer.

Walmart said Tuesday it will discontinue all sales of handgun ammunition and sales of short-barrel rifle ammunition that can be used with military-style weapons, following two "horrific" shootings at Walmart stores this summer. It will also stop all handgun sales in Alaska, marking its complete exit from the handguns category.

The biggest retailer in the world also is asking customers at Walmart and Sam's Club to no longer openly carry firearms in stores, in states where "open carry" is allowed, unless they are authorized law enforcement officers. Open carry legislation is currently on the books in more than 26 states, Dan Bartlett, executive vice president of corporate affairs, said during a call with members of the media.