“We are investigating the allegations raised in the New York Times and are working with MindGeek’s bank to understand this situation, in addition to the other steps they have already taken,” Mastercard said in a statement to Bloomberg News, referring to Pornhub’s parent company, which accepts Mastercard payments via an intermediary. “If the claims are substantiated, we will take immediate action.”

The investigations follow a Friday piece from New York Times columnist Nicholas Kristof, which highlighted a variety of alleged content on the site that puts its subjects in harm’s way, including the sexual assault of children, revenge porn, sex with unconscious people, spy camera videos, and other shocking content. Mr Kristof also interviewed young women who said their lives were ruined after videos of them as minors made it onto the site.

“Pornhub is unequivocally committed to combating child sexual abuse material, and has instituted a comprehensive, industry-leading trust and safety policy to identify and eradicate illegal material from our community,” the site, which gets 3.5 billion visits a month, told the Times in response to the article. It added that any claim it allows child porn on the site “is irresponsible and flagrantly untrue.”

Pornhub operates like YouTube in allowing users to upload their own videos. An estimated 6.8 million new clips are added every year. Pornhub says it has a team of human moderators who review every post before it goes up, as well as digital monitoring technologies that “fingerprint” harmful videos to keep them from being re-uploaded once flagged.

But a recent investigation from Vice found that the fingerprinting tech is easily evaded, and videos on Pornhub can be downloaded, so harmful content can continue circulating privately even once it’s taken down.

The allegations swiftly provoked outrage online and in the halls of power.

Activist investor Bill Ackman called on financial institutions like Visa and Mastercard to join PayPal, which stopped processing payments for the site last year.

“Owners of these sites should be criminally prosecuted if this continues,” he said in a Saturday tweet.

Following the reports, senator Josh Hawley of Missouri pledged to introduce a federal right to sue people exploited on sites like Pornhub.

“It’s time for it to end,” he said in tweet on Friday. “I will introduce legislation to create a federal right to sue for every person coerced or trafficked or exploited by sites like Pornhub.”

Pornhub is centered in Montreal, and the controversy reached Canadian prime minister Justin Trudeau as well.

“We are always extremely concerned with gender-based violence, with exploitation of minors, with child pornography,” Mr Trudeau said Friday. “We’re going to continue to work with police agencies and security agencies and all means possible to ensure that all Canadians are kept safe.”