NEW YORK (AP) — Pornhub said Tuesday it was halting unverified users from uploading video material after a report alleged that the pornographic website was showing videos of rape and underage sex.

Visa and Mastercard said over the weekend that they are investigating their business relationship with Pornhub after Nicholas Kristof, opinion columnist at The New York Times, wrote that the site also carries revenge pornography and other explicit video taken without consent of the participants.

Pornhub said that it doesn’t knowingly allow images of sexual abuse of children. But, in a blog post on Tuesday, the company listed steps it was taking to further protect against images of abuse and nonconsensual activity on its site.

Pornhub said next year it will announce ways in which individuals can become verified users. It will still allow new material from partners it knows, like porn production companies. The website has a huge volume of material: 6.8 million new videos were uploaded last year. The company could not say Tuesday what percentage of that was from unverified users.

Pornhub said it has hired a law firm to conduct an independent review of its content, has moderators that examine each video that is posted to the site and works with 40 organizations with a focus on child safety to monitor what it posts.

The company said that “every online platform has the moral responsibility” to join in the fight against depictions of child sexual abuse or non-consensual activity.

The site also said it was banning users from downloading material from its site.

The online payment service PayPal last year stopped processing payments to Pornhub, which is owned by the pornography conglomerate MindGeek. In his column, Kristof criticized other card issuers for working with the site.

Pornhub said it had more than 42 billion visits to its website last year, an average of 115 million a day.