US gun retailer Dick's Sporting Goods has announced it will no longer sell assault-style rifles in its more than 600 stores across the country.
The moves comes on the day students return to the Florida high school where 17 people were shot and killed two weeks ago.
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Dick's Sporting Goods CEO Edward Stack says supporting the students is the right thing to do.
"If these kids are brave enough to organise and do what they're doing, we should be brave enough to take a stand - and that's what we've done."
Nikolas Cruz shot 17 people dead on campus using an AR-15 style semi-automatic rifle which he had legally bought.
Mr Stack says when they realised they sold a shotgun to Cruz last November (not the weapon used in the shooting), they knew they needed to act.
"We had a pit in our stomach and said, we don't want to be a part of this story. We [have] a responsibility to these kids, and we decided we are not going to sell these anymore."
Dick's Sporting Goods has also stopped selling high-capacity magazines and won't sell any weapons at all to people under 21.
"Gun violence is an epidemic that's taking the lives of too many people," said Mr Stack, saying he expected a backlash from pro-gun rights customers.
Back to school
About 3,000 students, many carrying white flowers, wove through hundreds of uniformed police officers to get to class at Marjory Stoneman Douglas High School on Wednesday (US time).
The school district was easing them back into their routine with a half-day of classes scheduled to begin with what is normally the students' fourth period. That was where the students were in their day when a 19-year-old man who had been kicked out of the school is accused of beginning his rampage.
Not all of the sprawling school was reopened. The building where the 14 students and three educators were fatally shot on Februrary 14 will remain closed, officials said, as state lawmakers contemplate tearing it down and replacing it with a memorial to the victims.
Jeannine Gittens, 44, and Nia Hills, 47, drove to Douglas ahead of the bus their sons rode in to be there for their arrival.
"We just wanted to make sure they know we are there and that they have our support," said Gittens, who said her son Jevon, a 16-year-old junior, and his friend had ridden the bus "to make today feel as normal as possible."
The shooting inflamed the nation's long-running debate on gun rights as defined in the Second Amendment of the US Constitution. It also sparked a youth-led gun control movement featuring survivors of the attack in Parkland, Florida, who have already lobbied lawmakers in Florida's capital Tallahassee and Washington, DC.
"We will push for change and our children are going to be the change agents," Gittens said. "We see that things have to change and we are not going to stop until they do."
Freshman Nicholas Rodrigues, 15, said he decided to walk the mile from his home in neighboring Coral Springs rather than ride his bicycle as usual because "wanted to think about things".
Even as students went into the sprawling Douglas campus, supporters remained gathered outside.
"We feel for these kids so much," said Beverly Turner, a 63-year-old youth pastor, who said she had two children who graduated from the school. "We've seen them grow up and us being there for them is the least we can do."
US President Donald Trump has suggested arming teachers and reopening mental hospitals as a way of combating school violence.
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Mr Trump is scheduled to meet with a group of 17 senators and representatives from both parties later on Wednesday for a discussion on background checks and other proposals later on Wednesday, the White House said.
Following the shooting, several large American companies said they were ending programs that offered discounts or other benefits to NRA members.
Reuters / Newshub.