(Reuters) - Pornhub said on Tuesday it had banned users’ ability to download videos and would allow only certain partner accounts to upload content, following a newspaper column which said many videos posted on the adult website depicted sexual assault of children. The sex videos site, which has denied the allegations made in a New York Times column, said the new policies would be effective immediately and a new verification process would be implemented in the new year for users to upload videos. Payments provider Mastercard Inc said on Sunday it and the bank of Pornhub parent company MindGeek were investigating the allegations. Billionaire investor Bill Ackman called on Mastercard and Visa Inc to temporarily withhold payments to Pornhub following publication of the newspaper column, which described some videos on the site as recordings of assaults on unconscious women and girls. Mastercard and Visa did not immediately respond to requests for comment on Tuesday. Pornhub said it also was expanding its content moderation measures and will release a transparency report next year. The website said certain verified paid downloads would be exempt from the ban.