The world’s largest retailer said Thursday that customers can continue to purchase guns and ammunition by request. Walmart currently sells firearms at about half of its 4,700 U.S. stores.

“We have seen some isolated civil unrest and as we have done on several occasions over the last few years, we have moved our firearms and ammunition off the sales floor as a precaution for the safety of our associates and customers,” spokesman Kory Lundberg said in a statement on Thursday.

The company did not specify the incidents to which it was referring. But according to local media in Philadelphia, at least one Walmart store was ransacked after rioting broke out after the police shooting of Walter Wallace Jr., a Black man whose family said he was in the midst of a mental health crisis.