US retailers, with nearly 30,000 branches in the US, have opposed the open carrying of weapons in their stores. After the retailer Walmart, the pharmacies Walgreens and CVS joined the initiative. The companies have approximately 10,000 branches nationwide. The supermarkets Kroger and Wegmans, which together operate more than 3,000 branches, also asked all their customers not to carry open arms anymore. Exceptions are, of course, police.

"We support the efforts of individuals and groups working to prevent firearms violence," CVS said. The open carrying of weapons is allowed in the US in many states.

The retailer Walmart had said on Tuesday that the open carrying of weapons is no longer desirable in the more than 4,000 Walmart stores. There have been recent incidents in which employees or customers were scared. In some cases, branches had to be evacuated and the police notified. "These incidents are worrying and we would like to avoid them," it said. Misunderstandings could easily lead to "tragic results". The concealed carrying of weapons remains allowed.

Walmart wants to restrict the sale of ammunition

Walmart also wants to restrict the ammunition sale. The gun lobby had criticized this announcement. "It's shameful to see Walmart bow to pressure from anti-gun elites," the National Rifle Association (NRA) said. Customers would turn to other traders "who more support American fundamental rights." The NRA is one of the most powerful lobbying groups in the US.

The supermarket chain Kroger also joined Walmart's demand for stricter gun laws. It requires stronger customer audits prior to arms purchases, said a vice president of the company, Jessica Adelman, CNBC.

About a month ago, a massacre at a Walmart branch in El Paso, Texas, killed 22 people. A few days earlier, there had already been two deaths from gunfire at a Walmart in Southaven, Mississippi. "It's clear that the status quo is no longer acceptable," said Walmart chief Doug McMillon on Tuesday.

In the US, where weapons are usually very easy to buy, there are always cases where individuals shoot at passers-by in schools, shopping malls or other public places. It was not until Saturday that a gunman killed seven people in Texas and injured around 20 others, including a 17-month-old child.

After each of these cases, the discussion about stricter gun laws flares up in the US. But mostly without consequences - although surveys show that a majority of Americans want a bit stricter rules. Every year, around 40,000 people die from firearms use in the United States.