Facebook has reported the British Broadcasting Corporation (BBC) to the U.K. police after the media outlet sent the tech firm sexualized images of children it said the U.S. firm failed to remove from its website.
The BBC says it reported "dozens of photos" to Facebook using the site's own moderation system but the vast majority were not removed and so it then contacted Facebook to ask for an interview.
The broadcaster said it had sent Facebook the images after the firm's director of policy agreed to be interviewed but only on the proviso the BBC could provide examples of the improper material that had not been taken off Facebook's site.
However, instead of carrying out the interview to answer the claims, Facebook instead reported the BBC to the police.
Facebook provided CNBC with a statement Tuesday.
"We have carefully reviewed the content referred to us and have now removed all items that were illegal or against our standards," it said.
"This content is no longer on our platform. We take this matter extremely seriously and we continue to improve our reporting and take-down measures.
"It is against the law for anyone to distribute images of child exploitation.
"When the BBC sent us such images we followed our industry's standard practice and reported them to Ceop [Child Exploitation & Online Protection Centre].
"We also reported the child exploitation images that had been shared on our own platform. This matter is now in the hands of the authorities."
The BBC's director of editorial policy, David Jordan, questioned the move in a statement issued Tuesday.
"The fact that Facebook sent images that had been sent to them, that appear on their site, for their response about how Facebook deals with inappropriate images…the fact that they sent those on to the police seemed to me to be extraordinary," he said.
"One can only assume that the Facebook executives were unwilling or certainly reluctant to engage in an interview or a debate about why these images are available on the Facebook site."
In an email Tuesday, the U.K. National Crime Agency said it "does not routinely confirm or deny the existence of specific investigations".
Report by David Reid / CNBC