Facebook Inc (FB.O) prohibited global users from coordinating person-to-person private deals of arms on its online social network, and its Instagram photo-sharing service on Friday, Reuters reported.

Moreover, Facebook’s prohibition came in a countering effort against rising concerns that its services were increasingly being used to thwart background checks on gun purchases.

The move comes while the US debates the issue of access to guns after a string of mass shootings. U.S. President Barack Obama has urged social media companies to clamp down on gun sales organized on their platforms.

The prohibition of the arms’ sales updates Facebook’s regulated goods policy, introduced in March 2014 that banned people from selling marijuana, pharmaceuticals and illegal drugs.

However, licensed retailers are still able to advertise firearms on Facebook that lead to transactions outside of Facebook’s service.

Monika Bickert, Facebook’s head of product policy, said in a statement that “over the last two years, more and more people have been using Facebook to discover products and to buy and sell things to one another.”

Facebook is the world’s most popular online social network, with 1.59 billion users across the globe, 219 million of them residing in the US and Canada.

The National Rifle Association, a lobbying group opposed to limits on U.S. gun ownership rights, did not immediately respond to a request for comment. Nevertheless, groups advocating increased gun control policy applauded the implementation of the new measure.