A top Facebook executive admitted Wednesday that Russian agents had used the social network’s popular Messenger platform to interfere in the 2016 presidential election.

Facebook Messenger boss David Marcus disclosed that a “very small” number of the 470 accounts active in the Russian interference campaign were using Messenger to communicate with their users.

Marcus cautioned that the company was still determining, alongside federal investigators, how Russia-linked accounts may have tried to influence the U.S. political discourse last year. But he said inquiries “at this stage” showed that these accounts were not prolifically using his product.

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“My understanding is that it’s a very small number,” Marcus said at The Wall Street Journal’s D.Live conference in Laguna Beach, Calif. “The way that the platform was used is still being investigated right now on the Messenger side of things, but traditionally if you’re a page, for instance, you cannot message people. So people have to message you.”

Messenger was reportedly used by some pages with ties to Russian operatives. Marcus, like other Facebook executives, argued that the work done by Facebook around the world was being wrongly “overshadowed” by the Russia “narrative.”

“Clearly, when you design a platform that reaches 2 billion people every month, sometimes bad things happen and we shouldn’t tolerate those things,” Marcus said.

—By Theodore Schleifer, Recode.net.

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