WASHINGTON (REUTERS) - Russian President Vladimir Putin most likely directed an effort by Moscow to try to swing the 2020 US presidential election to Mr Donald Trump, according to an American intelligence report released on Tuesday (March 16) that sources said could trigger United States sanctions on Moscow.

The 15-page report, released by the US Office of the Director of National Intelligence, added heft to longstanding allegations that some of Mr Trump's top lieutenants were playing into Moscow's hands by amplifying claims made against then candidate Joe Biden by Russian-linked Ukrainian figures in the run-up to the Nov 3 election.

It also added new findings that Mr Putin either oversaw or at least approved of the election meddling to benefit Mr Trump.

Russia on Wednesday described the report as baseless. "The document prepared by the US intelligence community is another set of baseless accusations against our country for interfering in American domestic political processes," Russia's embassy in the United States said in a statement on Facebook.

"The conclusions of the report on Russia conducting influence operations in America are confirmed solely by the confidence of the intelligence services of their self-righteousness. No facts or specific evidence of such claims were provided."

Washington is expected to impose sanctions on Moscow as soon as next week because of the allegations, three sources said on condition of anonymity.

The findings about Mr Putin's role are likely to receive particular attention, given the report's conclusions that Russia-backed figures such as Ukrainian parliamentarian Andriy Derkach enlisted unnamed US political figures in their campaign to smear Mr Biden and his son Hunter.

The report named Mr Derkach, who met Mr Trump's lawyer Rudy Giuliani in 2019, as someone whose movements were tracked, if not directed, by Putin.

"Putin had purview over the activities of Andriy Derkach," the report said. "Other senior officials also participated in Russia's election influence efforts - including senior national security and intelligence officials who we assess would not act without receiving at least Putin's tacit approval."

Democrat Biden defeated the Republican Trump and became President in January.

US intelligence agencies and former special counsel Robert Mueller previously concluded that Russia also interfered in the 2016 US election to boost Mr Trump's candidacy with a campaign of propaganda aimed at harming his Democratic opponent Hillary Clinton.

Mr Mueller found extensive contacts between Mr Trump's campaign and Russia. Mr Trump, while he was President, also faced questions about ties by his associates with Russia and Russia-linked figures in Ukraine.

The US House of Representatives impeached Mr Trump in 2019 - the first of two times - on charges arising from his request that Ukraine investigate the Bidens.

The US intelligence report also found other foreign attempts to sway American voters in 2020, including a "multi-pronged covert influence campaign" by Iran intended to undercut Trump.

As president, Mr Trump pulled the United States out of a multilateral nuclear deal with Iran and imposed fresh sanctions.

China counter-narrative

The report also punctured a counter-narrative pushed by Mr Trump's allies that China was interfering on Mr Biden's behalf, concluding that Beijing "did not deploy interference efforts".

"China sought stability in its relationship with the United States and did not view either election outcome as being advantageous enough for China to risk blowback if caught," the report said.

US officials said they also saw efforts by Cuba, Venezuela and the Lebanese militant group Hizbollah to influence the election, although "in general, we assess that they were smaller in scale than those conducted by Russia and Iran".

The Russian, Chinese and Cuban Embassies in Washington did not immediately return messages seeking comment.

The Iranian mission to the United Nations and the Venezuelan Ministry of Information also did not immediately respond to requests for comment. Moscow, Beijing and Teheran routinely deny allegations of cyber espionage and election interference.

The White House did not respond to a request for comment on whether sanctions would be imposed on Russia as early as next week, which was first reported by CNN.

Asked about CNN's report, a US official said Mr Biden had "been clear" Washington would respond to destabilising Russian actions and noted US steps to respond to Russia's alleged use of a chemical weapon against Kremlin critic Alexei Navalny.

"There will be more soon," said the official on condition of anonymity.

Two sources told Reuters the sanctions could address the cyberhack blamed on Russia that used US company SolarWinds to penetrate US government networks, as well as reports that Russia offered bounties to Taleban-linked militants to kill coalition forces in Afghanistan.

Moscow has denied involvement in the hack and brushed off the bounties allegations.

The intelligence report assessed with high confidence that Russian leaders "preferred that former president Trump win re-election despite perceiving some of his administration's policies as anti-Russia".

A key role was played by another man with Russian intelligence ties, Mr Konstantin Kilimnik, according to the report.

It said Mr Kilimnik and Mr Derkach met and gave materials to Trump-linked people to push for formal investigations, and Mr Derkach released four audio recordings seeking to suggest that Mr Biden tried to protect his son Hunter from a corruption probe in Ukraine. Mr Giuliani was among those promoting such claims.

Mr Kilimnik was an associate of Mr Paul Manafort, who served as Mr Trump's 2016 campaign chairman. Mr Trump pardoned Mr Manafort last year for a criminal conviction stemming from Mr Mueller's investigation.

Russian agents also tried to hack subsidiaries of the Ukrainian energy company Burisma, "likely in an attempt to gather information related to President Biden's family", it said. Mr Hunter Biden had served on Burisma's board.