Facebook has deleted some of Mark Zuckerberg's private messages over fears sensitive data could be leaked.

Three sources claim old Facebook messages from Zuckerberg have disappeared from their inbox.

The recipients were not notified - raising concerns about what the Facebook CEO could be hiding.

Facebook claims the change was made after the 2014 Sony Pictures hack, when a mass data breach at the movie studio resulted in embarrassing email histories being leaked.

However, the lack of disclosure has angered some users, along with the absence of a similar tool to recall messages for normal users.

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Facebook founder Mark Zuckerberg (pictured) has secretly deleted his private messages over fears sensitive data could be leaked

An email receipt of a message from 2010 seen by TechCrunch proves some messages from the Facebook CEO no longer appear in chat logs or Facebook files.

The removal of these messages was not disclosed publicly and users were not informed.

Although Zuckerberg may be CEO of the company, the ability to remove messages from Messenger - now used by 1.3 billion people - is not allowed under the company's terms of service.

Users can only delete messages from their own inbox and they would still appear in the inbox of the recipient.

The fact the the company is prepared to make exceptions makes a mockery of its statement that it wants to 'make the world more open and transparent', say experts.

Facebook claimed these messages were deleted due to concerns about corporate security.

'After Sony Pictures' emails were hacked in 2014 we made a number of changes to protect our executives' communications', a spokesperson told MailOnline.

'These included limiting the retention period for Mark's messages in Messenger. We did so in full compliance with our legal obligations to preserve messages.'

Three sources have said old Facebook messages (stock image) from Zuckerberg have disappeared from their inbox and recipients were not notified - raising concerns about what the Facebook CEO could be hiding

The Sony hack targeted the emails of Sony film executives, revealing the inner workings of the industry.

Other Facebook-owned companies such as Instagram and WhatsApp have functions that mean users can delete messages.

Earlier this week the company was further embroiled in the scandal over user's private data.

It was revealed Facebook scans the contents of messages that people send each other on its Messenger app, blocking any content that contravenes its rules.

What users write in messages may also be read manually if it's flagged to moderators for breaching Facebook's community guidelines.

While the intentions behind the practice may be well-meaning, the news is likely to add to users' concerns over what the social network knows about them.

It follows revelations that the Trump-affiliated consulting firm obtained data on at least 50 million unsuspecting Facebook users.

Messenger says that it doesn't use data from messages it has scanned for the purposes of advertising, but that is likely to be of little comfort in the current climate, with privacy at the forefront of many Facebook user's minds (stock image)

WHAT HAS FACEBOOK DONE TO ADDRESS PRIVACY CONCERNS? Facebook is giving its privacy tools a makeover as it reels from criticisms over its data practices and faces tighter European regulations in the coming months. The changes won't affect Facebook's privacy policies or the types of data it gathers about its users. But the company hopes its 2.2 billion users will have an easier time navigating its complex and often confusing privacy and security settings. Facebook is giving its privacy tools a makeover as it reels from criticisms over its data practices and faces tighter European regulations in the coming months. This image shows how the settings will appear before (left) and after (right) the redesign Facebook says it's trying to make the controls easier to find and to give users a simpler way to access and download the data it collects on them. The announcement follows revelations that Trump-affiliated consulting firm got data on millions of unsuspecting Facebook users. Facebook is also facing criticism for collecting years of data on call and text histories from Android users. In a written statement, Erin Egan, vice president and chief privacy officer, policy, and Ashlie Beringer, vice president and deputy general counsel, said: 'Last week showed how much more work we need to do to enforce our policies and help people understand how Facebook works and the choices they have over their data. This image shows a redesign of Facebook's privacy tools. The changes won't affect Facebook's privacy policies or the types of data it gathers on users, but the company hopes users will have an easier time navigating its complex settings menus Among the changes, Facebook is making data settings and tools easier to find, is introducing a new privacy shortcuts menu, and is adding tools to find, download and delete your Facebook data 'We’ve heard loud and clear that privacy settings and other important tools are too hard to find and that we must do more to keep people informed. 'We’re taking additional steps in the coming weeks to put people more in control of their privacy. 'Most of these updates have been in the works for some time, but the events of the past several days underscore their importance.' Among the changes, Facebook is making data settings and tools easier to find, is introducing a new privacy shortcuts menu, and is adding tools to find, download and delete your Facebook data. Advertisement

This information was used to target voters in the US, based on psychological profiling, with political adverts spreading disinformation.

Facebook is also facing criticism for collecting years of data on call and text histories from Android users.

CEO Mark Zuckerberg confirmed the policy during a podcast interview with Vox's editor at large, Ezra Klein.

Zuckerberg told his host a story about receiving a phone call from staff at his Mountain View firm.

He was informed that their systems had blocked attempts to send inflammatory Messenger instant messages about ethnic cleansing in Myanmar.

About the experience, the 33-year-old billionaire said: 'In that case, our systems detect what's going on.

'We stop those messages from going through.'

The news has been met with mixed reactions on social media, with a number of users expressing concern.

Messenger says that it doesn't use data from messages it has scanned for the purposes of advertising, according to reports in Bloomberg.

The company told the website that it uses the same tools to prevent abuse in messages that are in place across Facebook as a whole.

Users are also able to flag posts or messages that they feel are in violation of the site's house rules.

This will either cause one of the social network's community operations team to manually review the content, or automated systems can also make decisions.