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Facebook Inc CEO Mark Zuckerberg returned to Capitol Hill on Wednesday for more questioning by lawmakers who have a rare chance to air grievances about the company directly to the head of the world's largest social media network.

The 33-year-old internet mogul testified at 10 a.m. EDT before the U.S. House of Representatives Energy and Commerce Committee, a day after he appeared for nearly five hours before a U.S. Senate hearing.

39 PHOTOS Facebook CEO Mark Zuckerberg testifies before Congress See Gallery Facebook CEO Mark Zuckerberg testifies before Congress WASHINGTON, DC - APRIL 10: Facebook co-founder, Chairman and CEO Mark Zuckerberg arrives to testify before a combined Senate Judiciary and Commerce committee hearing in the Hart Senate Office Building on Capitol Hill April 10, 2018 in Washington, DC. Zuckerberg, 33, was called to testify after it was reported that 87 million Facebook users had their personal information harvested by Cambridge Analytica, a British political consulting firm linked to the Trump campaign. (Photo by Chip Somodevilla/Getty Images) Facebook CEO Mark Zuckerberg arrives to testify before a House Energy and Commerce Committee hearing regarding the company?s use and protection of user data on Capitol Hill in Washington, U.S., April 11, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg arrives to testify before a House Energy and Commerce Committee hearing regarding the company?s use and protection of user data on Capitol Hill in Washington, U.S., April 11, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg testifies before a House Energy and Commerce Committee hearing regarding the company?s use and protection of user data on Capitol Hill in Washington, U.S., April 11, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the US Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee on Capitol Hill, April 10, 2018 in Washington, DC. / AFP PHOTO / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) Mark Zuckerberg, chief executive officer and founder of Facebook Inc., waits to begin a joint hearing of the Senate Judiciary and Commerce Committees in Washington, D.C., U.S., on Tuesday, April 10, 2018. Lawmakers will grill Zuckerberg on issues ranging from the troves of data vacuumed up by app developers and political consultant Cambridge Analytica to Russian operatives' use of the social network to spread misinformation and discord during the 2016 U.S. presidential election. Photographer: Andrew Harrer/Bloomberg via Getty Images Facebook founder and CEO Mark Zuckerberg arrives to testify during a Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee joint hearing about Facebook on Capitol Hill in Washington, DC, April 10, 2018. / AFP PHOTO / SAUL LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images) Facebook founder and CEO Mark Zuckerberg arrives to testify during a Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee joint hearing about Facebook on Capitol Hill in Washington, DC, April 10, 2018. / AFP PHOTO / SAUL LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images) Facebook CEO Mark Zuckerberg arrives to testify before a Senate Judiciary and Commerce Committees joint hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg arrives to testify before a Senate Judiciary and Commerce Committees joint hearing regarding the company?s use and protection of user data on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Aaron P. Bernstein Facebook CEO Mark Zuckerberg arrives to testify before a Senate Judiciary and Commerce Committees joint hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Aaron P. Bernstein The witness table is seen before Facebook CEO Mark Zuckerberg appearance at a joint hearing of the Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee on Capitol Hill, April 10, 2018 in Washington, DC. / AFP PHOTO / Brendan Smialowski (Photo credit should read BRENDAN SMIALOWSKI/AFP/Getty Images) Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the US Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee on Capitol Hill, April 10, 2018 in Washington, DC. / AFP PHOTO / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the US Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee on Capitol Hill, April 10, 2018 in Washington, DC. / AFP PHOTO / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the US Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee on Capitol Hill, April 10, 2018 in Washington, DC. / AFP PHOTO / JIM WATSON (Photo credit should read JIM WATSON/AFP/Getty Images) Facebook founder and CEO Mark Zuckerberg arrives to testify during a Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee joint hearing about Facebook on Capitol Hill in Washington, DC, April 10, 2018. / AFP PHOTO / SAUL LOEB (Photo credit should read SAUL LOEB/AFP/Getty Images) WASHINGTON, DC - APRIL 10: Facebook co-founder, Chairman and CEO Mark Zuckerberg arrives to testify before a combined Senate Judiciary and Commerce committee hearing in the Hart Senate Office Building on Capitol Hill April 10, 2018 in Washington, DC. Zuckerberg, 33, was called to testify after it was reported that 87 million Facebook users had their personal information harvested by Cambridge Analytica, a British political consulting firm linked to the Trump campaign. (Photo by Chip Somodevilla/Getty Images) Facebook CEO Mark Zuckerberg listens while testifying before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg takes a drink while testifying before a Senate Judiciary and Commerce Committees joint hearing regarding the company?s use and protection of user data on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Alex Brandon/Pool Facebook CEO Mark Zuckerberg takes a drink while testifying before a Senate Judiciary and Commerce Committees joint hearing regarding the company?s use and protection of user data on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Alex Brandon/Pool Facebook CEO Mark Zuckerberg testifies before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. Facebook CEO Mark Zuckerberg testifies before a Senate Judiciary and Commerce Committees joint hearing regarding the company?s use and protection of user data on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Aaron P. Bernstein Facebook CEO Mark Zuckerberg sits down following a break to resume testifying before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg sits down following a break to resume testifying before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Senator John Kennedy (R-LA) listens as Facebook CEO Mark Zuckerberg testifies before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Sen. Shelley Moore Capito (R-WV) listens as Facebook CEO Mark Zuckerberg testifies before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Senator John Kennedy (R-LA) (L) looks on as Senator Lindsey Graham (R-SC) holds up the privacy agreement of Facebook as its CEO Mark Zuckerberg testifies before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg responds to a question about his own personal information becoming public as he testifies before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis Facebook CEO Mark Zuckerberg testifies before a joint Senate Judiciary and Commerce Committees hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Aaron P. Bernstein Facebook CEO Mark Zuckerberg is surrounded by members of the media as he arrives to testify before a Senate Judiciary and Commerce Committees joint hearing regarding the company?s use and protection of user data, on Capitol Hill in Washington, U.S., April 10, 2018. REUTERS/Leah Millis TPX IMAGES OF THE DAY WASHINGTON, DC - APRIL 09: Facebook CEO Mark Zuckerberg (2 L) arrives at a meeting with U.S. Sen. Bill Nelson (D-FL), ranking member of the Senate Committee on Commerce, Science, and Transportation, April 9, 2018 on Capitol Hill in Washington, DC. Zuckerberg is scheduled to testify before a few Congressional committees this week on the mass users data Facebook has shared with political operatives. (Photo by Alex Wong/Getty Images) UNITED STATES - APRIL 9: Facebook CEO Mark Zuckerberg arrives for his meeting with Sen. Bill Nelson, D-Fla., in the Hart Senate Office Building on Monday, April 9, 2018. Zuckerberg is on Capitol Hill to testify before the House and Senate this week. (Photo By Bill Clark/CQ Roll Call) Mark Zuckerberg and Andrea Besmehn, Mark Zuckerbergs executive assistant at Facebook depart US Senator Bill Nelson's, D-Florida, office on Capitol Hill in Washington, DC, on April 9, 2018. Embattled Facebook chief Mark Zuckerberg has placed the blame for security lapses at the world's largest social network squarely on himself as he girded Monday for appearances this week before angry lawmakers.In prepared remarks released by a congressional panel, Zuckerberg admitted he was too idealistic and failed to grasp how the platform -- used by two billion people -- could be abused and manipulated. / AFP PHOTO / JIM WATSON / The erroneous mention[s] appearing in the metadata of this photo by JIM WATSON has been modified in AFP systems in the following manner: [Andrea Besmehn (R), Mark Zuckerbergs executive assistant at Facebook] instead of [Priscilla Chan]. Please immediately remove the erroneous mention[s] from all your online services and delete it (them) from your servers. If you have been authorized by AFP to distribute it (them) to third parties, please ensure that the same actions are carried out by them. Failure to promptly comply with these instructions will entail liability on your part for any continued or post notification usage. Therefore we thank you very much for all your attention and prompt action. We are sorry for the inconvenience this notification may cause and remain at your disposal for any further information you may require. (Photo credit should read JIM WATSON/AFP/Getty Images) WASHINGTON, DC - APRIL 09: Facebook CEO Mark Zuckerberg (C) leaves after a meeting with U.S. Sen. Bill Nelson (D-FL), ranking member of the Senate Committee on Commerce, Science, and Transportation, April 9, 2018 on Capitol Hill in Washington, DC. Zuckerberg is scheduled to testify before a few Congressional committees this week on the mass users data Facebook has shared with political operatives. (Photo by Alex Wong/Getty Images) WASHINGTON, DC - APRIL 09: Facebook CEO Mark Zuckerberg (3rd L) leaves after a meeting with U.S. Sen. Bill Nelson (D-FL), ranking member of the Senate Committee on Commerce, Science, and Transportation, April 9, 2018 on Capitol Hill in Washington, DC. Zuckerberg is scheduled to testify before a few Congressional committees this week on the mass users data Facebook has shared with political operatives. (Photo by Alex Wong/Getty Images) Mark Zuckerberg, chief executive officer and founder of Facebook Inc., exits after a meeting with Senator Dianne Feinstein, a Democrat from California, not pictured, on Capitol Hill in Washington, D.C., U.S., on Monday, April 9, 2018. Zuckerberg, in prepared testimony for the U.S. House of Representatives, said all of Facebook's problems are his mistake. Photographer: Yuri Gripas/Bloomberg via Getty Images WASHINGTON, DC - APRIL 09: Facebook CEO Mark Zuckerberg (C) leaves the office of Sen. Dianne Feinstein (D-CA) after meeting with Feinstein on Capitol Hill on April 9, 2018 in Washington, DC. Zuckerberg is meeting with individual senators in advance of tomorrow's scheduled hearing before the Senate Judiciary and Commerce committeees. Zuckerberg is under pressure to explain why tens of millions of Facebook user's private information was shared with Cambridge Analytica. (Photo by Win McNamee/Getty Images) WASHINGTON, DC - APRIL 09: Facebook CEO Mark Zuckerberg (C) leaves the office of Sen. Dianne Feinstein (D-CA) after meeting with Feinstein on Capitol Hill on April 9, 2018 in Washington, DC. Zuckerberg is meeting with individual senators in advance of tomorrow's scheduled hearing before the Senate Judiciary and Commerce committeees. (Photo by Win McNamee/Getty Images) WASHINGTON, DC - APRIL 09: Facebook CEO Mark Zuckerberg (3rd L) leaves after a meeting with U.S. Sen. Bill Nelson (D-FL), ranking member of the Senate Committee on Commerce, Science, and Transportation, April 9, 2018 on Capitol Hill in Washington, DC. Zuckerberg is scheduled to testify before a few Congressional committees this week on the mass users data Facebook has shared with political operatives. (Photo by Alex Wong/Getty Images) Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Zuckerberg endured a grueling five-hour testimony on Tuesday. He faced a multitude of questions on Facebook's privacy scandal involving the political data firm Cambridge Analytica's improper use of 87 million Facebook users' data, and Russia's misuse of the platform to promote political propaganda during the 2016 presidential election.

SEE ALSO: Mark Zuckerberg survived 5 hours of relentless questioning from Congress -- here's what you need to know

(Reuters contributed to this report, David Ingram and Dustin Volz)