(Adds details on sales change, CEO quotes, background)
WASHINGTON, Feb 28 (Reuters) - Dick's Sporting Goods Inc , a prominent seller of guns in the United States, said on Wednesday it will permanently stop selling assault-style rifles after the massacre at a Florida high school that has reopened a fierce debate over gun control in America.
The company will also stop selling high-capacity magazines and will not sell any guns to people under age 21, Dick's Chief Executive Ed Stack said in an open letter on the company's website and in television interviews.
"We're taking these guns out of all of our stores permanently," he told ABC News regarding the assault-style rifles.
Dick's announcement came as classes resumed at Marjory Stoneman Douglas High School in Parkland, Florida, where 17 people, mostly students, were killed two weeks ago in one of the deadliest U.S. mass shootings ever.
The massacre spurred a youth-led wave of protests, and state and national officials are considering whether to take gun control measures. The powerful National Rifle Association traditionally opposes such curbs, citing the right to bear arms under the U.S. Constitution's Second Amendment.
Dick's removed assault-style weapons from its Dick's-branded stores after the 2012 shooting at Sandy Hook Elementary School in Connecticut that killed 20 young children and six adults. Wednesday's move takes them out of its 35 Field & Stream outlets as well, Stack said, adding the measure would be permanent.
Dick's, based in Pennsylvania, was the latest company to take action after the Florida shooting. Other businesses have cut ties with the NRA and gun manufacturers.
Stack said Dick's respects the Second Amendment and law-abiding gun owners but was obliged to address a national gun epidemic that is killing too many children.
It was clear, especially after the Parkland shooting, that there were not enough systemic protections to prevent gun sales to people who are potential threats, Stack said in interviews on ABC and CNN, adding Congress must act to address issues such as tighter background checks and mental health.
The accused gunman, 19-year-old Nikolas Cruz, legally purchased a weapon at Dick's in November, although not the type used in the shooting, Stack said. Cruz, a former student at Stoneman Douglas, is accused of using an AR-15 assault-style weapon to carry out the killing.
"The systems that are in place across the board just aren't effective enough to keep us from selling someone a gun like that and so we've decided that we're not gong to sell the assault-type rifles anymore," Stack told ABC.
Stack said he knew the decision would upset some customers, but he cited the passionate response by the students and families in Parkland who are pushing for change.
"We have heard you," he wrote in his letter.
(Reporting by Susan Heavey Editing by Eric Walsh, Chizu Nomiyama and Frances Kerry)