President Barack Obama is promising that the U.S. will retaliate against Russia for its suspected meddling in America’s election process, an accusation the Kremlin has vehemently denied.

Amid calls on both sides of the political aisle on Capitol Hill for a full-bore congressional investigation, including assertions President Vladimir Putin was personally involved, Obama said in an interview that anytime a foreign government tries to interfere in U.S. elections, the nation must take action “and we will at a time and place of our own choosing.”

“Some of it may be explicit and publicized, some of it may not be,” he told NPR News Thursday. “But Mr. Putin is well aware of my feelings about this, because I spoke to him directly about it.”

White House officials said it was “fact” that Russian hacking helped Donald Trump’s campaign against Democratic presidential nominee Hillary Clinton. Administration officials on Thursday also assailed Trump himself, saying he must have known of Russia’s interference. Obama was to hold a news conference at the White House on Friday afternoon.

No proof was offered for any of the accusations, the latest to unsettle America’s uneasy transition from eight years under Obama to a new Republican administration led by Trump. The claims of Russian meddling in the election also have heightened already debilitating tensions between Washington and Moscow over Syria, Ukraine and a host of other disagreements.

In the NPR interview, Obama sough to contrast the current incident with “a traditional understanding that everybody’s trying to gather intelligence on everybody else.”

“One of the things we’re going to have to do over the next decade,” he said, is find an international understanding on rules involving what has become “a new game.” Obama said that U.S. officials should not let “the inter-family argument between Americans” obscure the need for people to “stand together” on this issue.

“My view is that this is not a partisan issue,” the president said, exhorting people to “take it out of election season and move it into governing season.”

Speaking to reporters earlier Thursday, presidential spokesman Josh Earnest said that “only Russia’s senior-most officials could have authorized these activities.”

Obama’s deputy national security adviser, Ben Rhodes, connected the dots further, saying it was Putin who 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.

The explosive accusation paints Putin, the leader of perhaps America’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 if not for Russia’s assistance. Nor has there has been any indication of tampering with the vote-counting.

The Kremlin rejected the claim of Putin’s involvement, with Putin spokesman Dmitry Peskov dismissing it as “laughable nonsense.”

There has been no specific, persuasive evidence shared publicly about the extent of Putin’s role or knowledge of the 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.

The dispute over Russia’s role is fueling 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 Russia was interfering to help his campaign.

That led Earnest to unload from the White House, arguing that 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.

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 “The 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.”

Trump struck back Friday morning, saying in a Twitter post, “Are we talking about the same cyberattack where it was revealed that head of DNC (Democratic National Committee) illegally gave Hillary the questions to the debate?” He was referring to a controversy centering on now-acting DNC chair Donna Brazile, who was accused of tipping off Clinton to questions that were to be asked in a debate hosted by CNN earlier this year. Brazile at the time was a CNN political analyst.

(AP)