Facebook Inc’s Instagram on Monday announced that long-term insider Adam Mosseri will take over as the new head of the photo-sharing app, a week after its co-founders resigned.

Mosseri, who joined Facebook in 2008, was most recently Instagram’s vice president of product. He had previously overseen Facebook’s news feed and spent a decade working closely with Facebook’s Chief Executive Officer Mark Zuckerberg.

In a blog post, the company's said Mosseri will oversee all functions of the business and will recruit a new executive team.

Co-founders Kevin Systrom and Mike Krieger resigned as chief executive officer and chief technical officer of Instagram last week giving scant explanation for the move.

Their departure from Instagram, Facebook’s fastest-growing revenue generator, followed the exit of Jan Koum, co-founder of Facebook-owned messaging app WhatsApp.

Last week, Systrom and Krieger said they planned to take time off and explore their “curiosity and creativity again”.

Shares of Facebook were down 1.3 percent at $162.35.