"We believe, based on the scope and sensitivity of these efforts, that only Russia's senior-most officials could have authorized these activities," the U.S. Intelligence Community said in a press release Friday.
WikiLeaks claimed the information came from emails from Clinton's campaign, though a Clinton spokesman would not verify their authenticity.
"Earlier today the U.S. government removed any reasonable doubt that the Kremlin has weaponized WikiLeaks to meddle in our election and benefit Donald Trump's candidacy," said Glen Caplin, Clinton's spokesman. "We are not going to confirm the authenticity of stolen documents."
Some of the excerpts indicate Clinton favors a common market and open borders.
"My dream is a hemispheric common market," one passage from a 2013 speech to Brazil's Banco Itau reads, "with open trade and open borders, some time in the future with energy that is as green and sustainable as we can get it, powering growth and opportunity for every person in the hemisphere."
The comments contradict efforts by Clinton to take a more critical stance on trade and the banking industry after facing a stiff challenge from Sen. Bernie Sanders, whose liberal positions forced Clinton to tack left in the primary.
Sanders, who has since endorsed Clinton, released a statement in response to the speech leaks, which Sanders called on Clinton to release in the primary. Sanders did not address the content of the leaks, but said he still supports implementing a Democratic platform he helped shape.
3. Don't have time to figure out which docs are real and which are faked...— John Podesta (@johnpodesta) October 7, 2016
"Whatever Secretary Clinton may or may not have said behind closed doors on Wall Street, I am determined to implement the agenda of the Democratic Party platform which was agreed upon by her campaign," he said. "Among other things, that agenda calls for breaking up the largest financial institutions in this country, re-establishing Glass-Steagall and prosecuting those many Wall Street CEOs who engaged in illegal behavior."
The released emails include exchanges with John Podesta, Clinton's campaign chairman, who tweeted that he believes the documents are faked.
"Don't have time to figure out which docs are real and which are faked," he said.
Podesta also echoed the allegation that the hack came from the Russian government.
"I'm not happy about being hacked by the Russians in their quest to throw the election to Trump," he said.