Internal Facebook emails, which initially appeared in a lawsuit filed by the software company Six4Three over the Silicon Valley company's privacy policy, was obtained by The Wall Street Journal, shedding light on some details of Facebook's data policy.

Facebook weighed an option of selling its users' private information several years ago, despite the promise of Mark Zuckerberg not to do so, The Wall Street Journal reported.

Internal Facebook documents, which were earlier seized by the UK Parliament, reportedly contained confidential correspondence between Facebook's senior executives and its CEO Zuckerberg.

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The content of the internal emails from between 2012 and 2014 was revealed Thursday by The Wall Street Journal, who reported that Facebook was considering selling access to its users' private information to companies that spend 'at least $250K a year'.

The emails revealed that there were discussions regarding the possibility of ‘pushing some advertisers to spend more in return for increased access to user information'.

Commenting on these emails, a spokesperson for Facebook said that it was just internal conversations and that the company was 'trying to figure out how to build a sustainable business'.

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Earlier in April, Mark Zuckerberg during a congressional hearing said: 'I can't be clearer on this topic: We don't sell data'.

Facebook has been investigated because of the scandal with Cambridge Analytica, a company that gathered information on millions of Facebook user accounts in order to better target political ads, allegedly impacting both the US presidential election and the UK Brexit referendum. Amid the investigation in the US, company CEO Mark Zuckerberg testified before a Senate committee.