WASHINGTON - The CIA concluded in a secret assessment that Russia intervened in the 2016 US election on behalf of President-elect Donald Trump, according to a report published in The Washington Post Saturday.

"Intelligence agencies have identified individuals with connections to the Russian government who provided WikiLeaks with thousands of hacked emails from the Democratic National Committee and others, including Hillary Clinton’s campaign chairman, according to US officials," the Post reported.

Russians allegedly used hacking groups to provide materials to WikiLeaks at the behest and direction of the Russian government, it said.

According to one unnamed senior US official, it was the "consensus view" of the intelligence committee that Russia's goal was to get Trump elected, the newspaper said.

The Trump transition team questioned the credibility of the CIA in response to the report. "These are the same people that said Saddam Hussein had weapons of mass destruction," the Trump transition team said in a statement. "The election ended a long time ago in one of the biggest Electoral College victories in history. It’s now time to move on and 'Make America Great Again'."

WikiLeaks founder Julain Assange has denied Russia was the source of the hacked emails his organisation released.

Trump has consistently disputed reports that Russian intelligence was working to help his campaign. In an interview with Time published this week, Trump said, “I don’t believe it. I don’t believe they interfered." He added that he believed the reports of Russian intervention were politically motivated.

Retired general Micahel Hayden, who served as CIA director during the Bush administration, was critical of Trump's refusal to accept the conclusion of the intelligence community.

"To have the president-elect of the United States simply reject the fact-based narrative that the intelligence community puts together because it conflicts with his assumptions. Wow," Hayden said at an event in Manhattan, according to CNN. "The data matters."

On Friday, President Obama ordered the nation's intelligence agencies to conduct a full review of attempts by foreign hackers to influence US elections, which he hopes can be completed before he leaves office on Jan 20.

Obama's homeland security adviser, Lisa Monaco, told reporters the report's results would be shared with lawmakers and others. "The president has directed the intelligence community to conduct a full review of what happened during the 2016 election process ... and to capture lessons learned from that and to report to a range of stakeholders, to include the Congress," she said during an event hosted by the Christian Science Monitor.

As summer turned to fall, Russian hackers turned almost all their attention to the Democrats. Virtually all the emails they released publicly were potentially damaging to Clinton and the Democrats, an official told Reuters.

"That was a major clue to their intent," the official said. "If all they wanted to do was discredit our political system, why publicise the failings of just one party, especially when you have a target like Trump?"

A second official familiar with the report said the intelligence analysts' conclusion about Russia's motives does not mean the intelligence community believes that Moscow's efforts altered or significantly affected the outcome of the election.

Russian officials have denied all accusations of interference in the US election.

A CIA spokeswoman said the agency had no comment on the matter.

The hacked emails passed to WikiLeaks were a regular source of embarrassment to the Clinton campaign during the race for the presidency.

US intelligence analysts have assessed "with high confidence" that at some point in the extended presidential campaign Russian President Vladimir Putin's government had decided to try to bolster Trump's chances of winning.

The Russians appear to have concluded that Trump had a shot at winning and that he would be much friendlier to Russia than Clinton would be, especially on issues such as maintaining economic sanctions and imposing additional ones, the official said.

Moscow is launching a similar effort to influence the next German election, following an escalating campaign to promote far-right and nationalist political parties and individuals in Europe that began more than a decade ago, the official said.

In both cases, said the official, Putin's campaigns in both Europe and the United States are intended to disrupt and discredit the Western concept of democracy by promoting extremist candidates, parties, and political figures.

In October, the US government formally accused Russia of a campaign of cyber attacks against Democratic Party organisations ahead of the Nov 8 presidential election. Obama has said he warned Putin about consequences for the attacks.