By DAMIAN J. TROISE
AP Business Writer

NEW YORK (AP) -- The rift between corporate America and the gun lobby is growing.

Retail heavyweights Walmart and Dick's Sporting Goods have taken steps to restrict gun sales. That follows moves by several other major corporations, including MetLife, Hertz and Delta Air Lines, that have cut ties with National Rifle Association following last month's school massacre in Florida.

Dick's said Wednesday it will immediately stop selling assault-style rifles and ban the sale of all guns to anyone under 21. Its CEO took on the NRA by demanding tougher gun laws.

Walmart, the nation's largest retailer, followed by saying it will no longer sell firearms and ammunition to people younger than 21. It had stopped selling AR-15s and other semi-automatic weapons in 2015.

The announcements from the major national retailers came as students at Marjory Stoneman Douglas High School in Parkland, Florida, returned to class for the first time since a teenager killed 17 students and educators with an AR-15 rifle two weeks ago.

"When we saw what the kids were going through and the grief of the parents and the kids who were killed in Parkland, we felt we needed to do something," Dick's Chairman and CEO Ed Stack said on ABC's "Good Morning America."

The announcements from Dick's and Walmart drew hundreds of thousands of responses for and against the moves on the companies' social media accounts.

"This is the moment when business leaders across the country get to decide if they want to stand on the right side of history," said Shannon Watts, founder of Moms Demand Acton for Gun Sense in America. "Mothers make the majority of spending decisions for their families, and we want to shop with businesses that care about the safety of our families - making this a smart business move, too."

Sporting goods chain Bass Pro Shops, which owns Cabela's, didn't respond to requests for comment. Nor did the Outdoor Retail Association or Gander Outdoors.

Dick Sporting Goods had cut off sales of assault-style weapons after the 2012 Sandy Hook Elementary School shooting. But sales had resumed at its smaller chain of Field & Stream stores, which consisted of 35 outlets in 16 states as of October.

On Wednesday, Stack said that would end, and he called on lawmakers to act now.

He urged them to ban assault-style firearms, bump stocks and high-capacity magazines and raise the minimum age to buy firearms to 21. He said universal background checks should be required, and there should be a complete database of those banned from buying firearms. He also called for the closing of the private sale and gun show loophole that enables purchasers to escape background checks.

"We support and respect the Second Amendment, and we recognize and appreciate that the vast majority of gun owners in this country are responsible, law-abiding citizens," Stack said in a letter. "But we have to help solve the problem that's in front of us. Gun violence is an epidemic that's taking the lives of too many people, including the brightest hope for the future of America - our kids."

Walmart said it was also removing items from its website that resemble assault-style rifles, including airsoft guns and toys. "Our heritage as a company has always been in serving sportsmen and hunters, and we will continue to do so in a responsible way," the retailer based in Bentonville, Arkansas, said.

One industry analyst said that other retailers that devote a small percentage of their business to hunting will probably follow suit. While guns can be bought from sporting goods stores or department stores, they can also be purchased online, at gun shows and from small local gun stores.

The NRA has pushed back aggressively against calls for raising age limits for guns or restricting the sale of assault-style weapons. Calls to the NRA were not immediately returned.

Stack also revealed that Nikolas Cruz, the 19-year-old arrested in the Florida attack, had bought a shotgun at a Dick's store within the past four months.

"It was not the gun, nor type of gun, he used in the shooting," the CEO wrote. "But it could have been. Clearly this indicates on so many levels that the systems in place are not effective to protect our kids and our citizens."

The vast majority of Dick's business is selling sporting goods like basketballs and sneakers. Joseph Feldman, a senior managing director at the Telsey Advisory Group, estimated that guns and ammunition account for 8 percent of the company's sales.

Dick's, which had net sales of $7.92 billion in the fiscal year that ended in January 2017, has a much bigger stake in youth sports.

Dick's is based just outside of Pittsburgh in a state where the first day of deer hunting season is an unofficial holiday for many families. Stack said Dick's is prepared for any backlash but will never allow the sale of such guns in its stores again.

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AP Retail Writers Anne D'Innocenzio and Joseph Pisani contributed to this report. Associated Press reporter Carrie Antlfinger contributed from Brookfield, Wisconsin.

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