Co-founders of photo sharing application Instagram Kevin Systrom and Mike Krieger on Monday announced their resignation as chief executive officer and chief technical officer of the company. Instagram is a Facebook-owned company.

Systrom and Krieger did not mention why they quit. In a blog post, Systrom said he and Krieger were taking some time off to “explore our curiosity and creativity again”.

Systrom said they were ready for the next chapter and hinted that they would build something new. “Building new things requires that we step back, understand what inspires us and match that with what the world needs; that’s what we plan to do,” Systrom wrote.

The pair notified the company’s leadership team and Facebook on Monday about their decision to leave, according to The New York Times.

Facebook’s co-founder and chief executive officer Mark Zuckerberg, in a statement, wished Systrom and Krieger “all the best and I’m looking forward to seeing what they build next.”

The resignation of Instagram co-founders comes just months after Jan Koum, the co-founder of WhatsApp, left the Facebook-owned company.

In 2012, Facebook acquired Instagram for $1 billion (Rs 7,283 crore). The app has more than 1 billion active monthly users and has grown by adding features like messaging and short videos. In 2016, it added the option of posting slideshows that disappear in 24 hours, a feature of Snapchat’s stories.