Wikileaks has published leaked emails from Democratic presidential hopeful Hillary Clinton, which could damage her bid to become president.

The whistle-blower website posted on Friday what it said were thousands of emails from Clinton's campaign chairman, John Podesta, including some with excerpts from speeches she gave to Wall Street executives and others - speeches she has declined to release despite demands from her Republican rival Donald Trump.

Excerpts of the speeches given in the years before her 2016 presidential campaign included some blunt and unguarded remarks to her private audiences, which collectively had paid her at least $26.1m in speaking fees.

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It was not immediately clear who hacked Podesta's emails, though the breach appeared to cover years of messages, some sent as recently as last month.

Among the emails was a compilation of excerpts from Clinton's paid speeches in 2013 and 2014.

It appeared campaign staff had read all Clinton's speeches and identified passages that could be potentially problematic for the candidate if they were to become public.

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One excerpt put Clinton squarely in the free-trade camp, a position she has retreated on significantly during the 2016 election.

In a talk to a Brazilian bank in 2013, she said her "dream" is "a hemispheric common market, with open trade and open borders" and asked her audience to think of what doubling American trade with Latin America "would mean for everybody in this room".

The emails also show that three years ago Clinton talked about the necessity of having two different positions on policy .

The excerpt reads "if everybody's watching, you know, all of the backroom discussions and the deals, you know, then people get a little nervous, to say the least. So, you need both a public and a private position."

In a separate speech to Goldman Sachs employees, Clinton said it was an “oversimplification” to blame the US banking system for the global financial crisis in 2008.

Only hours before the latest Wikileaks revelation, the US government formally accused Russia of conducting cyber attacks against American political organisations during the campaign for the November 8 presidential election, including hacking of Democratic Party emails.

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"We believe, based on the scope and sensitivity of these efforts, that only Russia's senior-most officials could have authorised these activities," said a joint statement from the Department of Homeland Security and Office of the Director of National Intelligence.

Clinton's team declined to confirm whether the emails leaked by Wikileaks are authentic, and instead emphasised Russia's potential involvement in the leak.

Podesta has said in a statement published on his Twitter account on Friday that he is not "happy about being hacked by the Russians in their quest to throw the election to Donald Trump".

"[I] don't have time to figure out which docs are real and which are faked ...," he said.

Clinton's trustworthiness was already under scrutiny because of the controversy over the use of a private email server while she was secretary of state.

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She has also faced criticism for her ties to large corporations and major banks.

In addition to her Republican critics, she has been attacked by Bernie Sanders, her D emocratic rival turned ally.

Sanders repeatedly criticised fellow Democrats for their close ties with corporations during his bid to become the party's presidential nominee.

"The Democratic Party has to reach a fundamental conclusion. Are we on the side of the working people or big money interests?" he once asked during his campaign.

The campaigns of both Sanders and Republican candidate Donald Trump won public support for their criticism of an allegedly rigged political system.

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The timing of the leak is also controversial, just 48 hours before Clinton meets Trump in their second TV debate and exactly a month before election day.

But a distracted Trump did not seem to notice, focusing instead on pushing attention towards Bill Clinton's past infidelities as he apologised for lewd and sexually charged comments he made about women back in 2005, also leaked on Friday.

"We will discuss this more in the coming days," he said at the end of his midnight video in which he apologised for his comments.

"See you at the debate on Sunday."

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Source: Al Jazeera News And Agencies