The statement comes a day after TheStreet reported that Facebook plans to launch a subscription-based news product, citing comments by Brown at a conference. Facebook will begin initial tests in October, TheStreet reported.

The feature is likely to allow publishers to create a paywall on Facebook's Instant Articles and guide readers to a publisher's home page to opt for a digital subscription, according to TheStreet.

Instant Articles lets publishers post articles directly to the Facebook app.

The idea for a paywall is based on premium and metered plans and has been in the works for a while, TheStreet said, citing Brown at the Digital Publishing Innovation Summit in New York.

Facebook also started the roll-out of a new tool that allows publishers using Instant Articles to measure how those articles perform compared with their own mobile websites.

Shares of Facebook closed up 0.79 percent at $164.14 on Wednesday.