The video sharing platform owned by Google said Wednesday it will prohibit any videos demonstrating how to remove firearm safety devices. In addition, videos showing homemade guns, automatic weapons and certain firearm accessories like silencers will be restricted to users 18 and older.

The changes take effect June 18 and come after gun safety advocates have repeatedly called on the platform to do more to ensure gun videos aren’t making their way to the site’s youngest users, potentially traumatizing children or sending them down dark paths of extremism and violence.

Katie Paul, director of the Tech Transparency Project, said the change was welcome news and a step in the right direction. But she questioned why the platform took so long to issue a new policy, and said her group will look to see how effectively YouTube enforces its new rule.

“Firearms are the number one cause of death for children and teens in America,” said Paul, whose group has long sought stronger age controls on online gun videos. “As always with YouTube, the real proof of change is whether the company enforces the policies it has on the books. Until YouTube takes real action to prevent videos about guns and gun violence from reaching minors, its policies remain empty words.”

Last year, researchers at Paul’s group created YouTube accounts that mimicked the behavior of 9-year-old American boys with a stated interest in video games. The researchers found that YouTube’s recommendations system forwarded these accounts graphic videos of school shootings, tactical gun training videos and how-to instructions on making firearms fully automatic.

One video featured an elementary school-age girl wielding a handgun; another showed a shooter using a .50 caliber gun to fire on a dummy head filled with lifelike blood and brains. Many of the videos violated YouTube’s own policies against violent or gory content.

Manhattan District Attorney Alvin Bragg last month called on YouTube to stop the proliferation of firearm-related videos to young users, and told the company it was failing to enforce its own policies. On Wednesday, Bragg said he applauded the company’s new policy.

“We have heard firsthand from young individuals that YouTube’s algorithm is driving them to the world of illegal and 3D-printed firearms, which is having a direct impact on the safety of Manhattanites,” Bragg said in a statement emailed to reporters.

YouTube said the policy changes were designed to reflect new developments, like 3D printed guns, which have become more available in recent years. YouTube requires users under 17 to get their parent’s permission before using their site; accounts for users younger than 13 are linked to the parental account.

“We regularly review our guidelines and consult with outside experts to make sure we are drawing the line at the right place,” said company spokesman Javier Hernandez.

Along with TikTok, YouTube is one of the most popular sites for children and teens. Both sites have been questioned in the past for hosting, and in some cases promoting, videos that encourage gun violence, eating disorders and self-harm.

Several perpetrators of recent mass shootings have usedsocial media and video streaming platforms to glorify violence, foreshadow or even livestream their attacks.