Walmart Inc. has removed all guns and ammunition from its shelves in response to worries about break-ins and to protect customers and staff as tensions across the U.S. have been escalating, the company says.

The world's biggest retailer sells guns in around half of its 4,700 stores across the U.S. It did not give details as to when it would put the firearms and ammunition back on display.

The move comes in the wake of peaceful demonstrations that led to looting and skirmishes in Philadelphia after the fatal police shooting of a black man, Walter Wallace Jr. It also comes days before the Nov. 3 U.S. presidential election, with many concerned that the outcome could be disputed or trigger civil unrest.

According to Walmart representative Kory Lundberg, the retailer has witnessed some violence and "as we've done on several occasions over the past few years, we've moved our firearms and ammunition off the sales floor as a precaution for the safety of our associates and customers," NBC News quoted Lundberg as saying in an emailed statement.

Walmart has removed firearms and ammo from its floors at different locations over the years, such as following unrest over the killing of unarmed black man George Floyd at the hands of police in late May this year, or after a surge in mass shooting incidents. The company said it will still sell the items upon request.

Firearm sales interest has climbed this year, a record of firearm background checks by the Federal Bureau of Investigation showed. The number of checks that has been carried out for 2020 - more than 28 million - has already exceeded the total number of checks for all of 2019.

The Bentonville, Arkansas-based retailer remains a major seller of firearms, although the group has cut numbers in recent years. In 2018, the retailer stopped selling guns to buyers under the age of 21. Firearm sales in the U.S. this year have hit record peaks, and a growing number of first-time customers have bought guns in recent months.