In a post on his Facebook page, the WhatsApp co-founder said he was leaving the smartphone messaging service and breaking with its parent company Facebook.

"It's been almost a decade since [co-founder Brian Acton] and I started WhatsApp, and it's been an amazing journey with some of the best people," Koum said in the post, adding: "But it is time for me to move on."

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His decision comes amid a data privacy scandal that has been dogging WhatsApp's parent company Facebook Inc. for weeks.

In response to Koum's post, Facebook CEO Mark Zuckerberg thanked Koum for teaching him more about encryption and "its ability to take power from centralized systems and put it back in people's hands."

"Those values will always be at the heart of WhatsApp," Zuckerberg said.

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Clash over personal data

Koum didn't provide a reason for his sudden departure, except to say that he wanted to spend more time "collecting rare air-cooled Porsches, working on my cars and playing ultimate Frisbee."

His exit is likely linked to clashes he had with Facebook over WhatsApp's strategy and the parent company's plans to use users' personal data and weaken the app's encryption, the Washington Post reported earlier on Monday.

WhatsApp currently claims to have over 1.2 billion users worldwide. The app quickly grew in popularity in part due to its policy of storing encrypted messages on users' smartphones and not on a central company server — making it more private.

Koum founded the messaging service along with Brian Acton in 2009. Facebook Inc. bought WhatsApp in 2014 for $19 billion (€15.7 billion). Acton left the company last September to start a non-profit.

Zuckerberg and other Facebook executives have spent weeks dealing with the fallout from a personal data scandal involving political consultancy Cambridge Analytica. It was revealed last month that the personal data of 87 million Facebook users wound up in the hands of Cambridge Analytica, a data mining firm tied to US President Donald Trump's 2016 presidential campaign.

rs/msh (AP, AFP, Reuters)

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