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WASHINGTON/SAN FRANCISCO, April 10 (Reuters) - Facebook Inc shares rose on Tuesday to their highest in almost three weeks as Chief Executive Mark Zuckerberg fended off questions from U.S. senators on how the social network handles user data and plans to counter attempts at interfering in U.S. elections.
Zuckerberg repeated his apologies made on Monday for a range of problems that have beset the world's largest social network, but the 33-year-old internet mogul broke little new ground in a joint hearing of the U.S. Senate's Commerce and Judiciary committees, raising investor hopes he could forestall strict regulation.
"We are going through a broad philosophical shift at the company," said Zuckerberg, wearing a dark suit and tie instead of his typical T-shirt and jeans.
Investors appeared to welcome his performance.
"Zuckerberg is conciliatory in his presentation," said Mariann Montagne, portfolio manager at Gradient Investments in Arden Hills, Minnesota. "The stock is running up on his comments. Maybe people like seeing Zuckerberg in a suit.
Facebook shares closed up 4.5 percent at $165.04.
Outside the U.S. Capitol building, online protest group Avaaz set up 100 life-sized cutouts of Zuckerberg wearing T-shirts with the words 'Fix Facebook.'
Facebook faces a growing crisis of confidence among users, advertisers, employees and investors after acknowledging that up to 87 million people, mostly in the United States, had personal information harvested from the site by Cambridge Analytica, a political consultancy that has counted U.S. President Donald Trump's election campaign among its clients.
It is also struggling to deal with fake news and alleged foreign interference in elections, disclosing in September that Russians under fake names used the social network to try to influence U.S. voters in the months before and after the 2016 election, writing about inflammatory subjects, setting up events and buying ads.
We believe it is entirely possible that there will be a connection there, Zuckerberg said when asked if there was overlap between Cambridge Analyticas harvested user data and the political propaganda pushed by the Kremlin-linked Internet Research Agency during the 2016 presidential election, which Facebook has said was seen by some 126 million people.
In February, U.S. Special Counsel Robert Mueller charged 13 Russians and three Russian companies with interfering in the election by sowing discord on social media.
Zuckerberg, who founded Facebook in his Harvard University dorm room in 2004, is fighting to prove to critics that he is the right person to go on leading what has grown into one of the world's largest companies.
On Friday, Zuckerberg threw his support behind proposed legislation requiring social media sites to disclose the identities of buyers of online political campaign ads.
(Reporting by Dustin Volz in Washington and David Ingram in San Francisco; Additional reporting by David Shepardson and Andy Sullivan in Washington, April Joyner in New York; Editing by Bill Rigby, Meredith Mazzilli and Peter Cooney)