Facebook profits soared in the third quarter as it brought in more than $10bn from advertising.
The firm said profits were $4.7bn (£3.5bn) in the three months to the end of September, up 80% year-on-year.
Chief executive Mark Zuckerberg told investors the firm's investments in security would "impact" profitability.
US lawmakers are examining the possible use of the platform for Russian propaganda activities during the 2016 US presidential election.
"We're serious about preventing abuse on our platforms," Mr Zuckerberg said. "Protecting our community is more important than maximising our profits."
Facebook has faced two days of questioning in Washington, with politicians asking for increased disclosure around political ads, and asking how the firm polices false content.
The firm said it was focused on protecting the "authenticity" of activity.
The firm said it had 2.07bn monthly active users at the end of September, up 16% year-on-year.
Shares in the firm jumped more than 1% in after-hours trade.
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