By John D. McKinnon and Brent Kendall
WASHINGTON -- The Federal Trade Commission this week questioned Facebook Inc. founder Mark Zuckerberg in its probe into whether the social-media giant has violated U.S. antitrust laws, according to a person familiar with the matter.
The move by the FTC suggests the agency is making progress in its investigation, which has focused in part on whether Facebook had a strategy of buying up potential rivals for the purpose of heading off future competitive threats.
"We are committed to cooperating with the U.S. Federal Trade Commission's inquiry and answering the questions the agency may have," a Facebook spokesman said.
Spokespeople for the FTC didn't immediately return a request for comment.
The testimony was first reported by Politico. The Wall Street Journal reported in July that the FTC was considering deposing the Facebook chief executive.
Mr. Zuckerberg wasn't deposed in the FTC's prior probe of Facebook for alleged consumer-privacy violations, a case that ended with a $5 billion settlement last year.
The testimony comes as the FTC has been under fire from some critics on Capitol Hill and elsewhere, who have questioned the agency's vigor in pursuing high-priority matters.
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