Facebook is prohibiting global users from selling firearms privately to each other through its online social network and its Instagram photo-sharing service. (Reuters)

It just became much harder to buy a gun through Facebook.

While Facebook itself doesn't sell guns, it has dealt for years with the right way to handle sales of regulated goods such as firearms, adult toys and prescription drugs on its social media network.

On Friday, the firm changed its policy regarding firearms, completely banning any peer-to-peer firearms sales on its network. That means users can no longer offer or coordinate the private sale of firearms on the site. This policy also applies to the sale of gun parts and ammunition, said a Facebook spokeswoman.

That's far more strict than the company's previous policy.

Two years ago, the company announced it would treat sales of firearms in the same way it handles alcohol, tobacco and adult products. Under the previous policy, those selling firearms were sent a message reminding them to comply with all rules and regulations. It also restricted access to those posts to users over the age of 18 and displayed an educational message to anyone who had searched for firearm sales on Facebook and Instagram. In general, advertisers are also not allowed to boost advertisements that feature any regulated goods on Facebook.

[Facebook to crack down on gun vendors]

The new policy brings the regulation of firearm sales in line with its bans on the sale of marijuana and prescription drugs on the network. If Facebook detects any posts that violates the new directive, it will review the posts and remove them if necessary.

When Facebook first addressed this policy in March 2014, it was in part at the behest of groups such as  Moms Demand Action for Gun Sense in America and Mayors Against Illegal Guns. According to the company, it decided to make this latest change in response to the way commerce has evolved on the network over the past two years.

"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," said Monika Bickert, Facebook’s head of global product policy. "We are continuing to develop, test and launch new products to make this experience even better for people and are updating our regulated goods policies to reflect this evolution."

This doesn't shut down all firearm sales activity on the site, however. Per the policy, licensed firearm retailers will still be allowed to post about their goods and services on Facebook, but they must complete those transactions off the network.

Facebook did not have data on how many sales are completed this way.

The policy change encouraged some gun control advocates, who see it as a way to crack down on transactions that potentially violate regulations on firearm sales.

“We spoke with Facebook regarding this important new policy decision, and I appreciate the company’s willingness to work with my office over the past two years on this issue," said New York Attorney General Eric Schneiderman. "Today's announcement is another positive step toward our shared goal of stopping illegal online gun sales once and for all.”

The National Rifle Association did not immediately respond to a request for comment.