Facebook users in America and France reported seeing their private messages posted publicly Monday as part of the Timeline feature, making them visible to anyone.

UPDATE: Facebook continues to insist there is no security issue. See below.

According to Slate, the issue was first reported in France, where the newspaper Le Monde called it "A Dark Day For Facebook."

Messages that were once private communications began showing up in users' 2011 and earlier timelines, which are posted as wall messages "posted by friends." Users can take them out of public view by clicking on the Edit option and selecting "Hide from Timeline."

It is not clear how many users have been affected. Facebook officials told Le Monde they were "in the middle of investigating to see whether this is a bug or not a bug."

In a statement, a Facebook spokesperson said company engineers "investigated these reports and found that the messages were older wall posts that had always been visible on the users' profile pages. Facebook is satisfied that there has been no breach of user privacy."

However, TechCrunch reporter Colleen Taylor responded with a screenshot showing private messages from a friend being displayed on her Facebook "Wall."

The Raw Story has also emailed Facebook asking for a comment on the issue. This story will be updated when the company responds.

UPDATE: A company spokesperson continued to deny the problem to TechCrunch, saying, "Every report we’ve seen, we’ve gone back and checked. We haven’t seen one report that’s been confirmed [of a private message being exposed]. A lot of the confusion is because before 2009 there were no likes and no comments on wall posts. People went back and forth with wall posts instead of having a conversation [in the comments of single wall post.]"

However, the BBC reported that users in England still reported seeing private material being revealed, including Poppy Dinsey, owner of What I Wore Today, a fashion social network.

"I'm 100% sure by content and from memory," Dinsey wrote. "And also some posts on my wall were clearly beginnings of (private) group [messages]."