WASHINGTON, Aug 24 (Reuters) - U.S. President Donald Trump criticized social media companies on Friday for silencing "millions of people" in what he called an act of censorship.

Trump did not mention any of the companies by name. On Tuesday, Facebook Inc (FB.O), Twitter Inc (TWTR.N) and Alphabet Inc (GOOGL.O) removed hundreds of accounts tied to an alleged Iranian propaganda operation, while Facebook took down a second campaign it said was linked to Russia.

"Social Media Giants are silencing millions of people. Can't do this even if it means we must continue to hear Fake News like CNN, whose ratings have suffered gravely. People have to figure out what is real, and what is not, without censorship!" Trump said.

(Reporting by Doina Chiacu; Editing by Lisa Lambert)

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