Pornhub, one of the world's most visited adult sites, is changing its rules over user uploads after being accused of hosting illegal videos.
A New York Times investigation accused the site of being "infested" with child-abuse and rape-related videos.
Pornhub said the claims were "irresponsible and flagrantly untrue".
But it has now said users must be verified to upload videos and removed its download function, which meant removed content could easily resurface.
The verification feature will launch in the new year, it said. For now, uploads have been removed for all users except industry professionals.
The move follows reports Visa and Mastercard had launched their own investigations into the claims.
If - as the New York Times article had urged - the two payment companies had suspended their services, it would have hit the website's owner, Mindgeek, financially.
Pornhub is generally free to use but offers a subscription service for higher-quality and exclusive videos.
The company has also now issued a statement promising "major steps to further protect our community".
What are accusations?
New York Times columnist Nicholas Kristof's investigation said searches for under-18s or specific ages of children yielded thousands of results.
And some people told Kristof they had been abused as children in the videos.
"Because it's impossible to be sure whether a youth in a video is 14 or 18, neither Pornhub nor anyone else has a clear idea of how much content is illegal," he wrote.
By Thomas Fabbri, BBC News
Adult performers and producers have been advocating for some of these changes for years, ever since sex video sites dramatically changed internet porn.
The ability for any user to freely download and upload content made it possible for pirated, stolen and illegal videos to proliferate, while also making sales of original content more difficult.
If fully implemented by PornHub and other sites, the new rules could have a significant impact in tackling illegal and pirated content, in a major victory for adult performers and non-consensual imagery campaigners.
However, the new policies are unlikely to satisfy the campaigners and lawmakers calling for PornHub to be shut down.
Internet porn has seen other important changes in recent years - driven by technology, social media, and subscription services like OnlyFans.
Pornhub has billions of visitors and millions of videos are uploaded every year.
Kristof was particularly critical of it allowing users to download videos and the payment-card providers' involvement.
What is changing?
"Effective immediately, only content partners and people within the Model Programme will be able to upload content to Pornhub," the site said in a statement.
And more users would be able to upload only when it launches its compulsory verification process.
It has also banned downloads for most users.
"In tandem with our fingerprinting technology, this will mitigate the ability for content already removed from the platform to be able to return," Pornhub said.
It had improved safety measures in recent months and would begin releasing a transparency reports in 2021.
Earlier this year, BBC News told the story of Rose Kalemba, who was raped at the age of 14 and then had to struggle to have a video of the attack removed from Pornhub.
Pornhub responded it had been under different ownership at the time, in 2009, and now had "the industry's most stringent safeguards and policies" in place to combat illegal content.