David Jackson, and Gregory Korte

USA TODAY

WASHINGTON — President-elect Donald Trump should support a probe of foreign interference in the presidential election, President Obama said Friday, arguing that his successor will have "a different set of responsibilities and considerations" once he's sworn in next month.

Obama laid the hacking operation — which exposed internal emails from the Democratic National Committee and the Hillary Clinton campaign to web sites and daily headlines — at the doorstep of Russian President Vladimir Putin.

"I will confirm that this happened at the highest levels of the Russian government," Obama said. "And I will let you make that determination as to whether there are high-level Russian officials who go off rogue and decide to tamper with the U.S. election process without Vladimir Putin knowing about it."

Questions about the Russian President's involvement in the hacking that roiled the U.S. presidential election dominated Obama's marathon end-of-year press conference on Friday. In an often reflective tone, Obama suggested some some national soul-searching about the role of "hyper-partisanship" in the debate about intelligence. "What is it about our political system that made us vulnerable to these kinds of potential manipulations?" he asked.

Obama said it seems some Republicans would rather believe Russia and its president, Vladimir Putin, than American officials who they see as somehow favoring the Democrats. He cited a poll that said 37% of Republican voters approve of Putin, a former KGB official.

"Ronald Reagan would roll over in his grave," he said.

But Obama said the United States can still confront Russia from a position of strength. "They are a smaller country. They are a weaker country. Their economy doesn’t produce anything that anybody wants to buy, except oil and gas and arms. They don’t innovate. But they can impact us if we lose track of who we are."

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FBI accepts CIA conclusion that Russians hacked to help Trump

Trump has disputed claims by intelligence agencies that Russia was behind the hacking of emails from Democratic officials. The president-elect and his aides have accused Democrats of pushing the Russia story in an attempt to de-legitimize his election win.

At the White House, Obama suggested he would retaliate against the Russians over the hack, but he did not say specifically how. The president said he personally told Putin to "cut it out," and there would be "serious consequences" for such actions. "There are times where the message will be directly received by the Russians and not publicized," he said.

Obama also said there is no evidence of Russian "tampering" with voting machines or the voting system.

Under criticism from some Democrats for not acting before Election Day, Obama told reporters he held off talking much about the hack attack back then because he didn't want partisan interference in the work of law enforcement and the intelligence community.

"It would become immediately just one more political scrum," he said. "I think we handled it the way it should have been handled."

Obama declined to say whether he thought Russian cyber espionage cost Democratic nominee Hillary Clinton the election, though he did assail the "troubling" news coverage of her candidacy — particularly the hacked message as disclosed by Wikileaks.

Citing one example, he mocked the media for reporting on the leaked risotto recipe of Clinton campaign chairman John Podesta. "You guys wrote about it every day, every single leak about every little juicy tidbit of political gossip," Obama told reporters.

Obama held his last scheduled news conference of 2016 on Friday before heading off on a two-week family vacation in Hawaii. The session clocked in at an hour and 27 minutes, a record for the Obama presidency.

The end-of-year meeting with reporters in the White House briefing room has become an annual tradition — a chance for the president to reflect on the successes and failures of the past year and begin to set the agenda for the next.

But this year's event featured a lame-duck Democratic president who is seeking to define and defend his legacy against a new Republican power structure that has promised to dismantle it.

During the news conference, Obama also:

► Declined to give his views on the decision by FBI Director James Comey to disclose new developments in the Clinton private email investigation just days before the election; Clinton aides have also blamed Comey for the Democratic candidate's surprising election loss.

► Called for an impartial international force to supervise evacuations from war-torn Aleppo, Syria. Obama denounced the "horrific violations of international law" in Aleppo and laid the blame on Syrian dictator Bashar al-Assad and his patrons in Russia and Iran.

► Acknowledged some personal regret and responsibility over the violent fate of Aleppo and Syria in general: “I ask myself every single day: is there something I could do to save lives and make a difference?" He also said he "cannot claim that we have been successful" with his strategy. He also noted that one of the alternatives would have been a dangerous and expensive U.S. "takeover" of Syria.

► Avoided comment on efforts by Trump opponents to get members of the Electoral College to vote against the president-elect next week. The president did describe the Electoral College as "a vestige, a carryover, from a different vision of our country."

► Suggested that Trump needs to think through any plans to change the "one China" policy in which the U.S. refuses to recognize Taiwan, and assess how mainland China might react to that. "For China, the issue of Taiwan is as important as anything on their docket," Obama said.

► Declared Thursday — the deadline for signing up for coverage under the Obama health care law — as the biggest day in Obamacare history, with more than 670,000 people signing up for coverage.