Walmart is removing signs, displays or videos that depict violence from its stores following a mass shooting at its eastern El Paso, Texas, location, during which 22 were killed.

The retailer instructed employees in an internal memo to remove any marketing material, turn off or unplug video game consoles that show violent games — specifically Xbox and PlayStation units — and to make sure that no violence is depicted on screens in its electronics departments.

Employees were also ordered to turn off hunting season videos in the sporting goods department.

Under the heading "Immediate Action," employees were instructed to "review your store for any signing or displays that contain violent images or aggressive behaviour. Remove from the sales floor or turn off these items immediately."

"We've taken this action out of respect for the incidents of the past week," said spokesperson Tara House in an email to The Associated Press on Friday.

The company's policy on selling video games that depict violence has not changed, nor has its policy on gun sales.

The killings in Texas, followed by another in Dayton, Ohio., just hours later that left nine dead, have put the country on edge.

Top Republicans cite video games

President Donald Trump and the top Republican in the House, Kevin McCarthy, each cited video games as a possible factor in the aftermath.

"We must stop the glorification of violence in our society. This includes the gruesome and grisly video games that are now commonplace," Trump said from the White House on Monday.

McCarthy, a day earlier, told Fox News, "the idea of these video games that dehumanize individuals to have a game of shooting individuals and others – I've always felt that is a problem for future generations and others."

Strauss Zelnick, the CEO of Take-Two Interactive, maker of the popular Grand Theft Auto series, scoffed at the criticisms this week, pointing to the popularity of all types of video games globally, including in countries not often afflicted with mass shooting events.

There is no known link between violent video games and violent acts.

Patrick Markey, a psychology professor at Villanova University in Pennsylvania who focuses on video games, found in his research that men who commit severe acts of violence actually play violent video games less than the average male.

About 20 per cent were interested in violent video games, compared with 70 per cent of the general population, he explained in his 2017 book Moral Combat: Why the War on Violent Video Games Is Wrong.

Democratic presidential candidate Seth Moulton commented on the retailer's move, with a reference to an online creed that has been linked to the suspect in the El Paso shooting,

"Hey @Walmart: there was a white nationalist manifesto. It wasn't the video games," said Moulton.

Retailer still a major gun seller

With respect to gun sales, Walmart last year said it would no longer sell firearms and ammunition to people younger than 21 after a teen was accused of killing 17 people at his former high school in Parkland, Fla.

Walmart Inc. stopped selling AR-15 guns and other semi-automatic weapons in 2015.

Springfield, Mo. police responded to a Walmart on Thursday afternoon after reports of a man with a weapon in the store. A suspect is now in custody. (Harrison Keegan/The Springfield News-Leader via AP)

Thomas Marshall, a 23-year-old category manager at a Walmart in San Bruno, Calif., started an online petition with change.org to encourage the parent company to drop its sales of weapons.

"We have one demand, and that is all — we value Walmart and our fellow associates, but we are no longer willing to contribute our labour to a company that profits from the sale of deadly weapons," reads the petition, which had been signed by over 54,000 as of midday Friday.

Employees in San Bruno and Portland, Ore., had walked out on Wednesday to protest the company's policy of selling firearms, Marshall told Reuters, adding some Walmart employees in New York also held a minute of silence that day.

A company spokesperson told Reuters on Thursday the policy on selling firearms had not changed.

"We have worked very hard to be a responsible firearms retailer... Walmart does more in the area of background checks than what the federal law requires," said Randy Hargrove.

Another Democratic presidential candidate, Bernie Sanders, in a social media post, urged the company to listen to employee feedback on the issue.

Walmart should respect the voices of its workers who are calling on the company to stop selling guns. I agree. This is exactly why I believe workers deserve representation on their board, so that their views are heeded. —@BernieSanders

Fellow candidate Julian Castro suggested on Twitter the company should get out of the business of selling guns.

"Video games don't cause mass shootings. Guns do," said Castro. "Maybe take those off the shelf, @Walmart?"

On Thursday, five days after the El Paso shooting, panicked shoppers fled a Walmart in Springfield, Mo., after a man carrying a rifle and wearing body armour walked around the store before being stopped by an off-duty firefighter.

Police on Friday identified the man as Dmitriy Andreychenko, 20, who lived in the Springfield area. Andreychenko was being held in the Greene County jail on suspicion of making a terrorist threat.

Since January 2017, Missouri has not required a permit to openly or conceal carry a firearm for those 19 years or older. Roughly 30 states allow the open carrying of handguns and rifles and shotguns in public without a permit.