TOPSHOT - Russian President Vladimir Putin (L) meets with his US counterpart Barack Obama on the sidelines of the G20 Leaders Summit in Hangzhou on September 5, 2016. / AFP / SPUTNIK / ALEXEI DRUZHININ        (Photo credit should read ALEXEI DRUZHININ/AFP/Getty Images)
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TOPSHOT - Russian President Vladimir Putin (L) meets with his US counterpart Barack Obama on the sidelines of the G20 Leaders Summit in Hangzhou on September 5, 2016. / AFP / SPUTNIK / ALEXEI DRUZHININ (Photo credit should read ALEXEI DRUZHININ/AFP/Getty Images)
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Story highlights

Dmitry Peskov said US accusations of hacking "look unseemly" without proof

US intelligence agencies have pinned blame on Russia for election-related hacking

(CNN) —  

The United States must either stop accusing Russia of meddling in its elections or prove it, a spokesman for Russian President Vladimir Putin said Friday.

Presidential spokesman Dmitry Peskov said it was “indecent” of the United States to “groundlessly” accuse Russia of intervention in the US election campaign, Russian state news agency Tass reported.

“They should either stop talking about that or produce some proof at last. Otherwise it all begins to look unseemly,” Peskov reportedly said about the latest accusations that Russia was responsible for hacker attacks.

President Barack Obama on Thursday vowed retaliatory action against Russia in the light of allegations that it meddled in the US presidential election campaign.

“I think there is no doubt that when any foreign government tries to impact the integrity of our elections that we need to take action and we will at a time and place of our own choosing,” he told NPR.

What is known about the hacking

• Data and thousands of emails were stolen from the Democratic National Committee and Hillary Clinton’s campaign chairman, John Podesta, among other targets.

• US intelligence agencies in October pinned blame on Russia for campaign-related hacking.

• WikiLeaks, which published much of the information obtained by hacking, has refused to reveal its sources.

• The United States has not alleged that Russia interfered with the voting process on Election Day.

’Sophisticated tools’

A US official familiar with the election-related hacking told CNN Thursday that the operation was carried out with sophisticated hacking tools, suggesting that Putin was involved.

The source said while Putin’s “fingerprints” were not on the hacking, “the nature of the operation was such that this had to be approved by top levels of the Russian government.”

READ MORE: Gloves-off White House creates rift between Obama, Trump teams

Russian cyberhacking activity has continued largely unabated since the election, including against US political organizations, US officials briefed on the investigation told CNN.

US President-elect Donald Trump dismissed the US intelligence community’s assessment, in comments Sunday.

OPINION: Russia’s role is shocking but no evidence vote was hacked

He suggested that there was no proof Russia had hacked the election, saying the snooping in Democratic Party servers and emails of Clinton campaign staffers could have been done by China or even someone sitting in New Jersey.

Clinton: Putin grudge was behind hack

Clinton said Thursday night that Putin’s alleged involvement in the hacking of Democratic organizations during the 2016 election stemmed from a longtime grudge the Russian President has held against her.

Meanwhile, her campaign chairman, Podesta, issued a scathing rebuke of the FBI.

He wrote in a Washington Post op-ed that the bureau’s “seemingly lackadaisical response to the very real Russian plot to subvert a national election” by comparison with its overzealous investigation of Clinton’s emails “shows that something is deeply broken” there.

Russian hacking and the 2016 election, explained

Saakashvili: It’s déjà vu

Former Georgian President Mikheil Saakashvili told CNN Friday that he was not surprised by the US claims against Russia.

“Well I almost was, like, vindicated when the same administration in Washington suddenly started to speak about Russian involvement in the election,” he said, speaking in the Ukrainian capital, Kiev.

“Because we, for me, it’s déjà vu. They were the same people telling us, “no, no, it cannot possibly be true.” And now it came to their doorsteps. And of course he [Putin] does all those things. Of course he is a great master.”

Intelligence expert tells White House, Trump to ‘shut up’

CNN’s Lindsay Isaac contributed to this report.