“It’s been almost a decade since Brian (Acton) and I started WhatsApp, and it’s been an amazing journey with some of the best people.

“But it is time for me to move on.”

WhatsApp co-founder Jan Koum said this on Monday while announcing that he is leaving Facebook.

Koum said in a post on his Facebook page that he is taking time off to pursue interests such as collecting air-cooled Porsches, working on cars and playing ultimate Frisbee.

ALSO READ: 'You Deserve Some Accolades', Aisha Buhari Tells Husband

US media reports indicated that a disagreement with Facebook over the privacy of user data may have also been a factor in Koum’s decision to quit his position as a high-ranking executive and likely leave his seat on the board at the leading online social network.

WhatsApp boasts more than 1.2 billion users worldwide.

In a reply to Koum’s post, Facebook co-founder and chief executive Mark Zuckerberg said he would miss working closely with the WhatsApp co-founder.

“I’m grateful for everything you’ve done to help connect the world, and for everything you’ve taught me, including about encryption and its ability to take power from centralized systems and put it back in people’s hands,” Zuckerberg said in his written reply.

“Those values will always be at the heart of WhatsApp.”