Facebook is tightening its gun policy. With over 1.5 billion monthly users, the social media giant known for serving users endless streams of food, pet and baby pictures had also grown into one of the world’s largest gun markets. A large number of those were sold through unlicensed dealers – individuals selling one or a few weapons to buyers.

On Friday the company announced it is no longer allowing private sales of guns on either Facebook or Instagram, which it also owns. Only licensed gun dealers will be allowed to advertise weapons for sale, with the transactions being arranged offline.

The move comes as unlicensed gun selling – which is legal but does not require a background check - has come under increased scrutiny in the U.S. Gun control advocacy groups have been lobbying Facebook for a move like this for some time, arguing that unlicensed gun sales make it easy for people who would otherwise fail background checks, like convicted felons, from getting their hands on weapons. One such group, Everytown for Gun Safety, says guns purchased in this way have been involved in at least two murders.

The issue extends beyond American borders, though – last month, a report surfaced that a significant amount of black market arms dealing in Iraq was conducted through Facebook. It was not immediately clear whether Facebook would seek to stamp out this type of activity as well.

Reports from over the weekend suggest that many private advertisements had not yet been taken down. That may be because Facebook indicated it would rely on users to report such ads as its primary enforcement tactic. If that's the case, it might be a while before things change.

(Sources: Slate, Mic, Wall Street Journal, New York Times, NPR)