A secret CIA assessment has found that Russia tried to tip last month's US presidential election in Donald Trump's favour, according to reports.

Outgoing President Barack Obama ordered a review of all cyberattacks during the 2016 election cycle, amid growing calls by US Congress on the extent of Russian interference in the process.

The Washington Post on Friday, citing an official, reported that individuals with connections to Moscow provided website WikiLeaks with emails hacked from the Democratic National Committee, Democratic nominee Hillary Clinton's campaign chief and others.

Those e-mails were steadily released through WikiLeaks in the months before the election and damaged Mrs Clinton's campaign.

The newspaper reported that the aim was to help Mr Trump win, not just to undermine the US election process.

The official was quoted as saying: "It is the assessment of the intelligence community that Russia's goal here was to favour one candidate over the other, to help Trump get elected."

WikiLeaks founder Julian Assange has denied links with Russia's government.

White House deputy press secretary Eric Schultz said Mr Obama had called for the cyberattack review this week to ensure "the integrity of our elections".

He said: "This report will dig into this pattern of malicious cyberactivity timed to our elections, take stock of our defensive capabilities and capture lessons learned to make sure that we brief members of Congress and stakeholders as appropriate."

The US president wants the report to be completed by his term ends on January 20th.

The Democratic Party has put pressure on the White House to reveal details of Russian hacking in the election.

On October 7th - a month before the election - the Department of Homeland Security and the Director of National Intelligence announced that "the Russian Government directed the recent compromises of e-mails from US persons and institutions, including from US political organisations".

Mr Trump's campaign team hit back at the CIA assessment, claiming "these are the same people that said Saddam Hussein had weapons of mass destruction".

His transition team added: "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'."