NEW YORK (AP) — Walmart will require customers to wear face coverings at all of its namesake and Sam’s Club stores, making it the largest retailer to introduce such a policy that has otherwise proven difficult to enforce without state and federal requirements.

The company said Wednesday that the policy will go into effect on Monday to allow time to inform customers. Currently, about 65% of its more than 5,000 stores and clubs are located in areas where there is already some form of government mandate on face coverings.

Bentonville, Arkansas-based Walmart joins a growing but still small list of retailers to require masks at all of its stores, filling the role of states and the federal government that have failed to issue such mandates on an issue that has been highly politicized by President Donald Trump and many of his ardent supporters. 

Given Walmart’s clout as the largest retailer in the U.S., its decision is expected to push others to issue similar mandates. In fact, hours after its announcement, supermarket chain Kroger Co. said it would follow suit starting July 22. 

“We are taking this extra step now because we recognize additional precautions are needed to protect our country,” Kroger said in a statement. 

Last week, Starbucks announced that customers who visit its company-owned cafe locations in the U.S. will be required to wear face coverings. The policies at Starbucks and Best Buy went into effect Wednesday. 

Only a handful of major retailers, including teen clothing chain American Eagle Outfitters and Apple, has a mask mandate for customers for all of its stores. Costco Wholesale Club was one of the first major retailers to require face coverings for customers at all of its stores. The policy went into effect in early May. 

The National Retail Federation, the nation’s largest retail trade group, said in a statement that it hopes Walmart’s move will be a “tipping point in this public health debate.”

Retailers had been hesitant to issue chain-wide mandates for fear of angering some customers. They also didn’t want to have their workers play the role of enforcers of the protocols. It was already hard enough to get some customers to comply even in the states that had the mandates. However, the recent surge of new virus cases - particularly in Florida, California, Texas and Arizona - has left them with no choice, retail experts say.

“I think Walmart’s decision will give cover to other retailers to require masks,” said Michael J. Hicks, an economist at Ball State University in Muncie, Indiana. “I applaud Walmart and others for stepping in.”

Bryan Eshelman, a managing director in the retail practice at consultancy AlixPartners, noted that retailers needed to step in to reduce their own health risks and that having a virus case is disruptive. 

“It is a business risk that they need to manage for the safety of employees and customers,” he said. 

Eshelman added that he believes making shoppers comply with the mask protocols will be easier now that wearing masks are becoming more of the norm.