U.S. President Barack Obama says the U.S. will retaliate against Russia for its suspected meddling in the general election process, an accusation the Kremlin has vehemently denied.

As the White House grew more bullish about suggesting Russian President Vladimir Putin was personally involved, Obama said he had spoken directly to Putin about his concerns. He said if a foreign government tries to interfere in a U.S. election, the nation must take action, "and we will at a time and place of our own choosing."

"We have been working hard to make sure that what we do is proportional, that what we do is meaningful," Obama said in an NPR News interview airing Friday.

​Obama's remarks were the clearest indication that whatever response the U.S. is planning, it hasn't happened yet. The White House has insisted for months that when the U.S. does retaliate, it might not be made public, a position that has created uncertainty about the strength and timing of any response.

Obama was expected to face questions about the alleged hacking and his response during a news conference at the White House on Friday afternoon.

'Produce some proof,' Moscow says

White House officials said it was "fact" that Russian hacking helped Donald Trump's campaign against Democratic presidential nominee Hillary Clinton. White House press secretary Josh Earnest on Thursday also assailed Trump himself over his refusal to acknowledge any hacking and his attacks on the U.S. intelligence community.

The tough talk from the White House fell flat in Moscow, where Putin spokesman Dmitry Peskov called the accusations baseless and inappropriate.

"They should either stop talking about that or produce some proof at last," Peskov told reporters Friday. "Otherwise it all begins to look unseemly."

U.S. officials told NBC News that Russian President Vladimir Putin orchestrated the U.S. election hacks. The Kremlin has dismissed the allegations and demanded proof. (Alexei Druzhinin/Sputnik via Reuters)

There has been no specific, persuasive evidence shared publicly about the extent of Putin's role or knowledge of any hackings. That lack of proof undercuts Democrats' strategy to portray Putin's involvement as irrefutable evidence of a directed Russian government plot to undermine America's democratic system.

But the White House pointed to a U.S. intelligence assessment released publicly in October that asserted "only Russia's senior-most officials could have authorized these activities." And Obama's deputy national security adviser, Ben Rhodes, connected the dots further, saying Thursday that Putin was responsible for the Russian government's actions.

"I don't think things happen in the Russian government of this consequence without Vladimir Putin knowing about it," he told MSNBC.

'Obvious' Trump knew, White House says

Trump struck back Friday morning, with a Twitter post mockingly asking, "are we talking about the same cyberattack" in which embarrassing information about the Democratic National Committee was also revealed. His tweet invoked emails stolen from Clinton's campaign chairman and later released publicly in hacking that has been linked to Russia.

Are we talking about the same cyberattack where it was revealed that head of the DNC illegally gave Hillary the questions to the debate? —@realDonaldTrump

The explosive accusation suggests Putin, the leader of perhaps the U.S.'s greatest geopolitical foe, as having directly undermined U.S. democracy. U.S. officials have not contended, however, that Trump would have been defeated by Clinton on Nov. 8 regardless of the alleged assistance by Russia, nor has there been any indication of tampering with the vote counting.

The dispute over Russia's role has also fuelled an increasingly public spat between Obama's White House and Trump's team that is threatening to spoil the delicate truce that Obama and Trump have forged since election day to smooth the billionaire businessman's move to the White House in little over a month.

​Kellyanne Conway, Trump's senior transition adviser, said it was "breathtaking" and irresponsible that the White House had suggested Trump knew about any Russian interference to help his campaign.

That led Earnest to unload from the White House, arguing Trump, who has dismissed the CIA's assessment of Russian interference, should spend less time attacking the intelligence community and more time supporting the investigation that Obama has ordered.

White House press secretary Josh Earnest said it was 'obvious' Trump knew Russia was interfering in the election. Allegations Russia was behind the DNC hacks have not been proven conclusively. (Yuri Gripas/Reuters)

Earnest said it was "obvious" Trump knew what Russia was doing during the campaign, pointing out that Trump had encouraged Moscow during a news conference to find Clinton's missing emails, repeating the assertion Obama made in a Daily Show appearance.

Trump has said he was joking.

"I don't think anybody at the White House thinks it's funny that an adversary of the United States engaged in malicious cyber activity to destabilize our democracy," Earnest said. "That's not a joke."