
Facebook CEO Mark Zuckerberg revealed in high-stakes testimony before Congress that his company is cooperating with special counsel Robert Mueller’s probe.

He also at first revealed that Facebook had gotten subpoenas from Mueller's investigators - only to walk back the account under questioning.

‘I Assume Facebook’s been served with subpoenas from special counsel Mueller’s office is that correct?’ asked senior Democratic Judiciary Committee member Sen. Patrick Leahy of Vermont.

‘Yes,’ Zuckerberg responded as his closely-watched testimony before a joint committee was underway.

‘Have you or anyone else at Facebook been interviewed by the special counsel’s office,’ Leahy, a former prosecutor, followed up.

Zuckerberg responded in the affirmative, but said he had not been personally interviewed.

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SURROUNDED: 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

‘Others have?’ Leahy asked.

‘I believe so,’ Zuckerberg tried to backtrack. Then he added: ‘I want to be careful here. Our work with the special counsel is confidential. And I want to make sure in an open session I’m not revealing something that’s confidential.’

‘I understand. I just want to make clear that you have been contacted, you have had subpoenas,’ Leahy followed up, without revealing where he got the information.

‘Let me clarify that I actually I am not aware of a subpoena. I believe that there may be. But I know that we’re working with them,’ Zuckerberg answered, as the exchange ended.

Investigation of 'tens of thousands' of apps

The exchange came as Zuckerberg got a televised grilling from lawmakers Tuesday and Wednesday in his first ever appearance before Congress, and immediately took heat for the role his social media site played in the elections.

Zuckerberg tried to reassure lawmakers, saying Facebook would investigate 'every single app that had access to a large amount of information' on the site.

'We believe that we're going to be investigating many apps – tens of thousands of apps,' he told Congress. 'And if we find any suspicious activity we're going to conduct a full audit of those apps to understand how they're using their data and if they're doing anything improper.

Before he could answer a single question, lawmakers went after Facebook for recent security breakdowns.

'There was clearly a breach of consumer trust and a likely improper transfer of consumer data,' said Senate Judiciary Chairman Charles Grassley of Iowa at the start of the hearing.

DRINK UP: Zuckerberg faced tough questions and lectures from lawmakers

In the well: Zuckerberg sat alone as he was questioned by the senators

Facebook 360: Zuckerberg was at the center of interest not seen in a tech CEO on Capitol Hill for more than two decades

Question time: 'We have made a lot of mistakes in running the company,' Zuckerberg admitted. 'It's pretty much impossible I believe to start a company in your dorm room and then grow it to be at the scale that you're at now without making some mistakes,' he said, alluding to the famous story of Facebook's creation.

Not all positive: One of the Facebook CEO's aides seem less pleased with progress

Leading the questioning: Chairman of the Senate Commerce, Science and Transportation Committee John Thune (left) and Chairman of the Senate Judiciary Committee Chuck Grassley(right) convened the joint session

Members of the audience hold up signs and wear sunglasses that read 'Stop Spying' before CEO Mark Zuckerberg arrives to testify before a joint hearing of the Commerce and Judiciary Committees on Capitol Hill in Washington, Tuesday, April 10, 2018

TROLLING: A woman wearing a blue and green pointy wig, aiming to look like a Russian troll, arrives before Facebook CEO Mark Zuckerberg arrives at a joint hearing of the Commerce and Judiciary Committees on Capitol Hill in Washington, Tuesday, April 10, 2018

Zuckerberg at first said under questioning that his firm had received a subpoena from special counsel Robert Mueller – then backed off and said he wanted to be 'careful' because 'our work with the special counsel is confidential.'

'Let me clarify that I actually I am not aware of a subpoena. I believe that there may be. But I know that we're working with them,' he responded after an exchange with Sen. Patrick Leahy (D-Vt.).

Pressure from left and right

'We've seen the apology tours before,' complained Connecticut Sen. Richard Blumenthal at one point, producing a poster with Zuckerberg's various statements of regret.

'You have refused to acknowledge even an ethical obligation to have reported this violation of the [Federal Trade Commission] consent decree' involving the firm, he said. 'I have no assurance that these kinds of vague commitments are going to produce action,' he fumed.

Grassley said his panel would hold another hearing on the Cambridge Analytica consulting firm and Internet privacy.

'We have made a lot of mistakes in running the company,' Zuckerberg admitted. 'It's pretty much impossible I believe to start a company in your dorm room and then grow it to be at the scale that you're at now without making some mistakes,' he said, alluding to the famous story of Facebook's creation.

Called to account for Russian exploitation

Leading Judiciary Democratic Sen. Dianne Feinstein called out an infamous Russian troll factory whose members have now been indicted and who exploited Facebook to boost Donald Trump in the 2016 campaign.

'We've seen how foreign actors are abusing social media platforms like Facebook to interfere in elections and take millions of Americans' personal information without their knowledge in order to manipulate public opinion and target individual voters,' said Feinstein as the 33-year old CEO faced a bank of 44 U.S. Senators.

'What is Facebook doing to prevent foreign actors from interfering in U.S. elections?' Feinstein asked him.

Not sworn: Mark Zuckerberg was not made to swear an oath but it would be contempt of Congress if he did not tell the truth

Ready for the apology: Zuckerberg settles in before testimony which started with his attempt to apologize.

'I think everyone should have control over how their information is used,' said Zuckerberg

'This is an arms race,' Zuckerberg said of Russians trying to exploit the platform

'There was clearly a breach of consumer trust and a likely improper transfer of consumer data,' said Senate Judiciary Chairman Charles Grassley of Iowa

'If you and other social media companies do not get your act in order, none of us are gonna have any privacy any more,' said Sen. Bill Nelson (D-FL)

'This is one of my top priorities in 2018 is to get this right,' Zuckerberg responded. 'One of my greatest regrets in running the company is that we were slow in identifying the Russian information operations in 2016.'

'There are people in Russia whose job it is, is to try to exploit our systems … So this is an arms race,' Zuckerberg said.

Said Democratic Sen. Bill Nelson of Florida: 'Let me just cut to the chase. If you and other social media companies do not get your act in order, none of us are gonna have any privacy any more. That's what we're facing.'

Nelson, who met with Zuckerberg Monday and faces a competitive reelection, said: 'I think you're genuine. I got that sense in conversing with you. You want to do the right thing. You want to enact reforms. We want to know if it's going to be enough.'

Charged with anti-conservative bias

Sen. Ted Cruz of Texas accused Facebook of bias shutting out conservative voices, saying the firm had 'blocked' Trump-loving performers Diamond & Silk from its site. The duo who were regulars at Trump campaign rallies wrote tweeted that Facebook had sent them a message saying: 'The Policy team has came to the conclusion that your content and your brand has been determined unsafe to the community.'

Last year Facebook limited distribution of their content, but did not shut down their page, the Wall Street Journal reported.

Trump 2020 campaign manager Brad Parscale tweeted in response: ''Senator @tedcruz is right. Why @DiamondandSilk? Why the attack on conservative voices?'

Zuckerberg was in Washington to address lawmakers in a packed hearing room inside the underground Capitol Visitors Center in one of the year's most closely-watched hearings.

Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the Commerce and Judiciary Committees on Capitol Hill in Washington, Tuesday, April 10, 2018, about the use of Facebook data to target American voters in the 2016 election

SHOWTIME: Facebook co-founder, Chairman and CEO Mark Zuckerberg (R) 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

CEO of Facebook Mark Zuckerberg testifies before the Senate Commerce, Science and Transportation Committee and the Senate Judiciary Committee joint hearing on 'Facebook, Social Media Privacy, and the Use and Abuse of Data' on Capitol Hill in Washington, DC

Where did you stay last night?

It wasn't just Zuckerberg but his enormously successful service that was put on trial.

'Mr. Zuckerberg, would you be comfortable sharing with us the name of the hotel you stayed in last night?' asked Illinois Democratic Sen. Richard Durbin at one point.

'Ah … no,' Zuckerberg replied.

'If you've messaged with anybody this week would you share the names of the people you've messaged?' he asked.

'Senator no I would probably choose to not do that publicly here,' he said.

Durbin responded: 'I think that may be what this is all about. Your right to privacy, the limits to your right to privacy and how much you give away in modern America in the name of quote connecting people around the world.'

'I think everyone should have control over how their information is used,' Zuckerberg answered.

Sen. Orrin Hatch of Utah defended the business model lets Facebook make a profit without charging users, relying on ad sales.

'You said back then that Facebook would always be free. Is that still your objective?' asked Hatch.

'Senator, yes, there will always be a version of Facebook that is free. It is our mission to try to help connect everyone around the world,' Zuckerberg responded.

Asked by Minnesota Democratic Sen. Amy Klobuchar whether he backed a rule requiring users be notified of any breach within 72 hours, he said: 'That makes sense to me.'

The 33-year tried to make inroads with some of the lawmakers who will sit on the dais for the televised spectacle – weeks after revelations of the massive extent of a security breakdown that allowed tens of millions of users have personal data get into the hands of consulting firm Cambridge Analytica.

The daily revelations set up Zuckerberg to draw fire both from Republicans who are hearing concerns from their millions of constituents and Democrats who infuriated about how Russian efforts to try to tilt the elections took advantage of the site.

Facebook CEO Mark Zuckerberg arrives to testify before a joint hearing of the Commerce and Judiciary Committees on Capitol Hill in Washington, Tuesday, April 10, 2018, about the use of Facebook data to target American voters in the 2016 election

Lawmakers from two Senate committees, representing almost half the Senate, will get a crack at questioning him.

Staff aides and members of the public lined up Tuesday for the hearing of a joint Senate Committee, and photographers crammed into a hearing room, jostling for position to get the best images of the Facebook founder for an event the generated headlines for weeks.

TIME TO FACE THE MUSIC: Avaaz.org Campaign Director Nell Greenberg, (L), walks among dozens of cardboard cut-outs of Facebook CEO Mark Zuckerberg while holding a protest outside of the U.S. Capitol building in Washington, U.S., April 10, 2018

In just a small taste of what Zuckerberg will have to endure, Delaware Democratic Sen. Chris Coons complained that there were took fake Facebook accounts pretending to be him – with Russia connections on display.

'On today of all days, I just found out that there are two fake Facebook accounts impersonating me, and guess what? Many of the 'friends' appear to be Russian accounts,' wrote Coons, a Judiciary Committee member. 'Mr. Zuckerberg-this is unacceptable,' he wrote in advance of the hearing.

LINING UP: People wait in line for a joint hearing with Facebook CEO Mark Zuckerberg before the Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee on Capitol Hill, April 10, 2018 in Washington, DC

Zuckerberg testifies before an unusual Senate Judiciary and Commerce Committees, followed by the House Energy and Commerce Committee on Wednesday.

Apologies

In advanced testimony released Monday, Zuckerberg said that he's 'sorry' and that his firm 'didn't do enough' to protect the sites' users from having their personal information compromised.

The 33-year-old exec will make the apology when he testifies about how millions of users had their data harvested by filling out surveys that got to Cambridge Analytica.

UNDER THE LIGHTS: 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

QUESTION TIME: The committee room is set up before Facebook CEO Mark Zuckerberg appears before a joint hearing of the Commerce and Judiciary Committees on Capitol Hill, Tuesday, April 10, 2018, in Washington

Zuckerberg defended Facebook as an 'idealistic and optimistic' company, before accepting personal responsibility for not setting up the right security protocols.

On Monday he toured senators' offices surrounded by Capitol Hill officers, with his disclosed meetings including Democrats Dianne Feinstein and Bill Nelson.

'It was my mistake, and I'm sorry,' he said, in House testimony released a day before his first grilling.

Closely-guarded: Mark Zuckerberg was surrounded by Capitol Hill cops as he toured senators' offices Monday before blockbuster testimony which will start on Tuesday

Entourage: The Facebook CEO was accompanied by advisers and escorted by Capitol Hill officers as he met senators including Dianne Feinstein

Zuckerberg said he was 'sorry' he didn't do enough to protect Facebook users' privacy

Visit: Mark Zuckerberg leaves his Bill Nelson, Democratic senator from Florida

Facebook presence: Andrea Besmehn

'But it's clear now that we didn't do enough to prevent these tools from being used for harm as well,' according to Zuckerberg's prepared testimony.

'That goes for fake news, foreign interference in elections, and hate speech, as well as developers and data privacy.'

He continued: 'We didn't take a broad enough view of our responsibility, and that was a big mistake. It was my mistake, and I'm sorry. I started Facebook, I run it, and I'm responsible for what happens here.

Zuckerberg's many apologies Facebook Inc has often angered users by its handling of personal information. Almost as often, Chief Executive Mark Zuckerberg has apologized. He did so again on Monday in written testimony to U.S. Congress, and will likely repeat that on Tuesday and Wednesday as he faces congressional committees looking into Facebook's management and protection of user data. Here is a collection of Zuckerberg's apologies, from the earliest to the most recent, in which he acknowledges mistakes and promises to do better. September 2006 Facebook started aggregating posts from each member´s friends into a new feature called News Feed, which was not a major privacy issue but agitated many users. Zuckerberg said: 'We really messed this one up. When we launched News Feed and Mini-Feed we were trying to provide you with a stream of information about your social world... We didn't build in the proper privacy controls right away.' November 2007 Facebook introduced a feature named Beacon that told a user's friends what they just bought, unless they blocked the disclosure of each purchase. It took Facebook several days to recognize it had a problem and to quell the outcry. Zuckerberg said: 'Weve made a lot of mistakes building this feature, but we´ve made even more with how we´ve handled them. We simply did a bad job with this release, and I apologize for it... Instead of acting quickly, we took too long to decide on the right solution. I´m not proud of the way we´ve handled this situation and I know we can do better.' February 2009 Facebook changed its terms of service, and its users reacted with suspicion. Zuckerberg said: 'We´re at an interesting point in the development of the open online world where these issues are being worked out.' For a look at Facebook's numbers: http://tmsnrt.rs/1SKTFU3 April 2010 The Wall Street Journal reported its discovery that Facebook allowed advertisers to access unique user IDs, which can be used to track consumers. It took the company a month to respond as the outcry from users and privacy advocates grew. Zuckerberg said: 'Sometimes we move too fast -- and after listening to recent concerns, we're responding.' He continued: 'In the coming weeks, we will add privacy controls that are much simpler to use. We will also give you an easy way to turn off all third-party services. We are working hard to make these changes available as soon as possible.' November 2011 Facebook signed a consent decree with the U.S. Federal Trade Commission after an investigation of its privacy violations. Zuckerberg said: 'I'm the first to admit that we've made a bunch of mistakes. Recently, the U.S. Federal Trade Commission established agreements with Google and Twitter that are helping to shape new privacy standards for our industry. Today, the FTC announced a similar agreement with Facebook.' - Reuters Advertisement

'So now we have to go through every part of our relationship with people and make sure we're taking a broad enough view of our responsibility,' he pledged.

After mentioning the estimated 126 million people who got content linked to the infamous Russian troll farm Internet Research Ageny, Zuckerber wrote: 'There's no question that we should have spotted Russian interference earlier.'

Zuckerberg is trying to earn some 'likes' from lawmakers, meeting privately Monday with some of those who will question him on the firm's privacy scandal later this week.

Facebook Founder and CEO Mark Zuckerberg met with lawmakers privately on Monday in advance of public hearings Tuesday and Wednesday, where he is expected to get a pounding from lawmakers angry about privacy issues

SO SORRY: Zuckerberg apologized in testimony released by the House Energy and Commerce Committee

The secret Monday meetings come in advance of Zuckerberg's Tuesday testimony before the House Energy and Commerce Committee and Wednesday before a joint hearing with the Senate Judiciary and Commerce panels.

The closed-door meetings run through Monday afternoon and include some of the members who will question Zuckerberg, Reuters reported.

The world's fifth richest man is being coached by a team of experts and a former George W. Bush aide about how to handle lawmakers waiting for the chance to interrupt him or bash Facebook's security practices.

He has retained a team from the top law firm WilmerHale as well as outside consultants. It even set up mock-hearings with consultants playing members of Congress, the New York Times reported.

OPEN DOOR: Facebook CEO Mark Zuckerberg arrives on Capitol Hill in Washington, Monday, April 9, 2018, to meet with Sen. Bill Nelson, D-Fla., the ranking member of the Senate Commerce Committee

Facebook CEO Mark Zuckerberg (3rd L) arrives at a meeting with U.S. Sen. Bill Nelson (D-FL), ranking member of the Senate Committee on Commerce, Science, and Transportation, as a member of the media tries to approach him April 9, 2018 on Capitol Hill in Washington, DC

PUT ME IN COACH: Zuckerberg has been getting coaching from Reginald Brown, who served as a special assistant and associate White House counsel to President George W. Bush

The behind-the-scenes prepping comes as Zuckerberg negotiated a media tour in which he accepted responsibility and the firm put out the bad and then worse news of how many millions of people had their data compromised.

'Their goal is to make Mr. Zuckerberg appear as humble, agreeable and as forthright as possible,' the Times reported, in a report sourced to people close to the operation.

One member of the team is Reginald Brown, who served as a special assistant and associate White House counsel to President George W. Bush.

Zuckerberg told reporters in a conference call he accepted blame for the policy that allowed political consulting firm Cambridge Analytica to acquire personal data on up to 87 million users.

Facebook has suspended another firm, CubeYou, after CNBC reported it engaged in a similar practice, relying on user surveys purportedly for academic research that then yielded information that ended up getting sold for commercial uses.

The company sold the data collected by researches for the Psychometrics Lab at Cambridge University.

'These are serious claims and we have suspended CubeYou from Facebook while we investigate them,' said a Facebook spokesman.

'If they refuse or fail our audit, their apps will be banned from Facebook.'

Facebook has been rolling out a PR strategy to deal with the scandal, but Zuckerberg is expected to face tough questioning in the televised hearings.

'A day of reckoning is coming for websites like @facebook,' tweeted Massachusetts Democratic Senator Ed Markey on Friday. 'We need a privacy bill of rights that all Americans can rely upon,' he wrote.

Zuckerberg's private sit-downs with lawmakers come after a decade where the firm ramped up its Washington presence – and political contributions.

Facebook has given $7 million in campaign contributions to lawmakers since 2007, according to the Center for Responsive Politics.

That includes $985,000 to members of the three committees that will interrogate Zuckerberg Tuesday and Wednesday.

A Facebook spokesman said on Sunday that the company plans to begin telling the estimated 87 million users affected by the breach associated with Cambridge Analytica on Monday.

A massive breach of Facebook data could have 'absolutely' affected more than 87 million users, former research director of Cambridge Analytical Christopher Wiley said on Sunday.

'I think that it could be higher, absolutely,' the computer expert turned whistle blower said during an interview with NBC's 'Meet the Press' Sunday.

Wylie revealed last month that Cambridge Analytical had improperly collected the data of millions of Facebook users without their consent

File - This Jan. 17, 2017, file photo shows a Facebook logo being displayed in a start-up companies gathering at Paris' Station F, in Paris. Facebook is on the offensive to try to contain swirling concerns about how it protects the data of its 2.2 billion members. As CEO Mark Zuckerberg prepares to face Congress on Tuesday, April 10, 2018, and the company rolls out new privacy rules, the social media juggernaut is facing the most serious challenge in its 14-year-history and seeking to maintain people's trust and avoid a user exodus.(AP Photo/Thibault Camus, File)

London-based Cambridge Analytica, which has counted U.S. President Donald Trump's 2016 campaign among its clients, has disputed Facebook's estimate of the number of affected users.

Zuckerberg is expected in his testimony to recognize a need to take responsibility and acknowledge an initial failure to understand how many people were affected, a person briefed on the matter, who asked for anonymity, said on Sunday.

Zuckerberg said in a conference call with reporters last week that he accepted blame for the data leak, which has angered users, advertisers and lawmakers, while also saying he was still the right person to head the company he founded.

On Friday, Facebook backed proposed legislation requiring social media sites to disclose the identities of buyers of online political campaign ads and introduced a new verification process for people buying 'issue' ads.

The steps are designed to deter the kind of election meddling and online information warfare that U.S. authorities have accused Russia of pursuing, Zuckerberg said on Friday. Moscow has denied the allegations.

In February, U.S. Special Counsel Robert Mueller charged 13 Russians and three Russian companies with interfering in the 2016 U.S. presidential election by sowing discord on social media.

Zuckerberg, on the call with reporters, said Facebook should have done more to audit and oversee third-party app developers like the one hired by Cambridge Analytica in 2014.