Walmart employees are urging the corporation to end its sale of firearms in the wake of mass shootings at its El Paso, Texas, store and in Dayton, Ohios downtown district a weekend of violence that killed 31 people and injured more than 50 others.

On Wednesday, Thomas Marshall, a manager in Walmarts San Bruno, California, e-commerce office, organized a walkout and encouraged his colleagues to sign a Change.org petition demanding that the corporation one of the nations largest retailers of guns and ammunition cease profiting from firearm sales.

The petition, which was created by Marshall and a colleague, has already amassed more than 55,000 signatures from employees and the public.

We value Walmart and our fellow associates, but we are no longer willing to contribute our labor to a company that profits from the sale of deadly weapons, it reads. We would like to see Walmart take a unified and public stance against guns and gun violence.

The call to action cited Saturdays El Paso massacre in which a gunman opened fire with an AK-47-style rifle , leaving 22 people dead, and a separate incident on July 30 at a Walmart in South Haven, Mississippi , where a disgruntled employee was charged with shooting and killing two co-workers.

Adding to the death toll, a shooting at Californias Gilroy Garlic Festival last month killed three people, and nine were killed Sunday in Dayton.

Marshall told HuffPost on Friday that 40 employees participated in the San Bruno walkout, and he helped to organize another at a Walmart e-commerce office in Portland, Oregon.

On Friday, a Walmart spokesperson told HuffPost that she feels there are better ways to speak out.

There are many more constructive avenues for associates to offer feedback, such as emails or leader conversations, and the vast majority of associates who want to share their views are taking advantage of those options, she said.

Marshall said he has already faced retaliation for speaking out, having been shut out of Walmarts server this week, unable to log in to his laptop and access email or a messaging program. He was also spoken to privately by a human resources representative, who told him that if he wasnt in the office, he didnt need access to the server an explanation he called a very thin excuse and immediately suspect.

Now Marshall is concerned he may be fired, noting that, although he has faith in the laws of this country that employees have very, very rigid protections when it comes to free speech, I know that Ill never be promoted in this company.

In 2015, Walmart banned assault-style rifles from being sold in its stores, but gun control advocates like Marshall are calling on the corporation to do more.

Stores are now being directed to temporarily take down violent video game displays , which spokeswoman Tara House said was out of respect for the incidents of the past week.

Among Republicans , including President Donald Trump , video games have become a talking point following mass shootings as certain members of the GOP claim the violence depicted in entertainment influences shooters. However, overall, research has come to no strong conclusion on that theory.

On the sale of guns, House said Walmart will continue a thoughtful and thorough review of our policies, providing no indication change will occur.

So far, Marshall has described his companys response to the violence as tone-deaf and very disappointing, chalking it up to thoughts and prayers.

Marshalls next step is to send the petition to Walmart CEO Doug McMillon.

In a statement released Wednesday , McMillon said he felt shock, anger and grief over the shootings, but made no mention of gun sales.

Well be thoughtful and deliberate in our responses, and will act in a way that reflects our best values and ideals, focused on the needs of our customers, associates and communities, he wrote.