US retail giant Walmart announced it will be raising its age restriction to 21 for firearm and ammunition purchase.
The company said it would raise the age of purchasing guns from 18 to 21 years old and remove online items - including toys - resembling assault-style rifles.
"In light of recent events, we've taken an opportunity to review our policy on firearm sales. Going forward, we are raising the age restriction for purchase of firearms and ammunition to 21 years of age. We will update our processes as quickly as possible to implement this change," a statement from Walmart read.
Walmart's new policy follows ending all sales of modern sporting rifles, including the AR-15, in 2015.
Earlier on Wednesday, Dick's Sporting Goods - a prominent seller of guns in the US - says 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 on Wednesday.
Mr Stack, who is a gun owner himself, said it was time for a nationwide reform around gun control.
"We're taking these guns out of all of our stores permanently," he told ABC News regarding the assault-style rifles.
"This is a complex issue, it's not just about guns, it's about mental health reform, it's around background checks and we hope they [Congress] come together with the intent of really finding a solution to this problem rather than just talking about it knowing they will never do anything.
"We are a staunched supporter of the Second Amendment, I am a gun owner myself, but we have just decided - based on what has happened and with these guns - we don't want to be apart of this story. We have eliminated these guns permanently."
Dick's Sporting Good's decision to remove assault rifles from its stores was met with high praise on social media.
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 US mass shootings ever.
The mass shooting spurred a youth-led wave of protests, and state and national officials are considering whether to take gun control measures.
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, Mr Stack said, adding the measure would be permanent.
Dick's is the latest company to take action after the Florida shooting. Other businesses have cut ties with the powerful National Rifle Association and gun manufacturers.
Guns on display at the Dick's Sporting Goods in Danvers, Massachusetts, USA, 28 February 2018. Source: AAP
It was clear, especially after the Parkland shooting, there were not enough systemic protections to prevent gun sales to people who are potential threats, Mr 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, Mr 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 going to sell the assault-type rifles anymore," Mr Stack said.
