Gregory Korte

USA TODAY

WASHINGTON — President Obama promised to retaliate against Russia for its attempts to undermine the U.S. elections process, saying that the United States would take action "at a time and place of our own choosing."

That threat came in an interview with National Public Radio to be broadcast Friday morning. And he said the response may not be obvious. "Some of it may be explicit and publicized; some of it may not be," he said.

The remarks were the strongest language yet from Obama since the intelligence community concluded in October that the hacking of email accounts belonging to the Democratic National Committee and Hillary Clinton campaign officials was authorized by "Russia's senior-most officials."

That, the White House has suggested, means that Russian President Vladimir Putin himself directed the attacks. "I don't think things happen in the Russian government of this consequence without Vladimir Putin knowing about it," Obama's deputy national security adviser, Ben Rhodes, told MSNBC.

The allegations of Russian interference were raised during the presidential campaign won by Republican Donald Trump last month. But the issue re-erupted last week after Obama ordered an intelligence review of malicious cyber activity by foreign powers in the last three presidential elections.

That review is expected to be completed before Obama leaves office on Jan. 20, and will "give us a comprehensive and best guess" as to the motivations of the hacking. Until now, intelligence agencies have said only that Russia "intended to interfere with the US election process," not necessarily to get Trump elected.

But Obama noted that the emails only benefited Trump, although he made clear that he was not suggesting that Trump himself was actively involved. "They understood what everybody else understood, which was that this was not good for Hillary Clinton's campaign," he said.

Putin has denied the allegations, and Trump has disputed the unanimous consensus of 16 intelligence agencies and the Department of Homeland Security. "If Russia, or some other entity, was hacking, why did the White House wait so long to act? Why did they only complain after Hillary lost?" he tweeted Thursday.

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Trump continues to push back on Russia hacking claims

Q&A: Why the CIA, FBI differ on Russian election hacking

Obama said he could't put the sole blame for Clinton's loss on the emails, which were released on Wikileaks and similar web sites. But he said they were one factor. "There's no doubt that it contributed to an atmosphere in which the only focus for weeks at a time, months at a time were Hillary's emails, the Clinton Foundation, political gossip surrounding the DNC," he told NPR.

The White House has declined to elaborate on what the potential retaliation against Russia would look like.

"The United States retains significant, extensive cyber capabilities that exceed the capabilities that are wielded by any other country in the world. And to detail those cyber capabilities would be to potentially undermine our ability to use them," White House press secretary Josh Earnest said Thursday. "But there are a range of proportional responses that the president and his team believe would be an appropriate response."