Walgreens announced Thursday it was asking customers to "no longer openly carry firearms" in its stores. Authorized law enforcement officials would be exempt from the request, the second-largest pharmacy chain, with 9,560 stores, said in a statement.

The announcement comes two days after Walmart asked its customers not to openly carry firearms in stores — even in states where it is permitted. Walmart also said that it would discontinue the sale of ammunition used in high-capacity magazines and military-style weapons. Walmart CEO Doug McMillon said the retailer will stop selling short-barrel rifle ammunition, such as the .223 and 5.56 caliber, which can be used in high-capacity magazines and military-style weapons.

Ohio-based supermarket chain Kroger, which has nearly 2,800 stores nationwide, also said this week it is asking shoppers not to openly carry guns in any of its stores.

The retail chains' measures follow mass shootings around the country in the past two months that have claimed dozens of lives.

On Saturday, in the West Texas sister cities of Midland and Odessa, Seth Ator, 36, opened fire after a routine traffic stop, killing seven people and injuring more than 20 others. He was killed by police outside a movie theater.

Last month, on Aug. 3, 22 people were killed by a shooter in a Walmart in El Paso, Texas. The next day, on Aug. 4, a gunman in a popular nightlife district in Dayton, Ohio, shot nine people to death.