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.”
Mr Zuckerberg last year said the idea that fake news on Facebook influenced the election was “pretty crazy”.
On Wednesday, the firm said almost 150 million people may have seen Russian propaganda efforts.
Facebook shared the figure during two days of tense questioning in Washington.