Zuckerberg slams Apple in an earnings call, casting Facebook as a victim

"We increasingly see Apple as one of our biggest competitors," Zuckerberg said, noting that Apple's iMessage software is preinstalled on iPhones - enabling it to become the most widely used messaging service in the U.S., unlike Facebook's WhatsApp - and that Apple's growing investment in services also enables it compete with Facebook and other apps that use its iOS software platform.

"Apple has every incentive to use their dominant platform position to interfere with how our apps and other apps work, which they regularly do," he said. "They say they are doing this to help people, but the moves clearly track their competitive interests."

Zuckerberg's comments, at a moment when the social network is being accused of major antitrust violations by the U.S. Department of Justice, seemed intended to paint a picture of Facebook as a service that is not a monopoly because it faces significant competitive threats, and to point out that its rival tech giant is even more powerful than Facebook. Apple is the world's wealthiest company by market capitalization; Facebook is the sixth.

Zuckerberg also accused Apple of providing false assurances on user privacy. He said that while Apple claims its iMessage software is encrypted and privacy-protecting, the company stores a backup of people's messages. He compared that practice to WhatsApp, which does not.

He also reiterated messaging from Facebook that upcoming changes to Apple's iPhone software would disproportionately harm both Facebook and small businesses that rely on personalized advertisements to reach customers and find new ones. Apple says that it made its policy change to limit data collection in order to protect user privacy.