President Donald Trump has followed up an apparent admission that Russia interfered with the US election by accusing Hillary Clinton of colluding with the Democrats to beat rival Bernie Sanders.

“Hillary Clinton colluded with the Democratic Party in order to beat Crazy Bernie Sanders. Is she allowed to so collude? Unfair to Bernie!” President Trump tweeted late Sunday night (AEST).

Hacked emails from the Democratic National Committee and released on WikiLeaks during the 2016 presidential election showed Democratic officials criticised the Senator Sanders, despite publicly appearing neutral.

Hillary Clinton colluded with the Democratic Party in order to beat Crazy Bernie Sanders. Is she allowed to so collude? Unfair to Bernie!

— Donald J. Trump (@realDonaldTrump) June 25, 2017

President Trump’s attack on Mrs Clinton comes after he criticised Barack Obama in a series of tweets Friday night for his inaction over the Russian interference.

Mr Trump wrote that Mr Obama “knew far in advance of November 8th about election meddling by Russia” and “did nothing about it”.

The sensational tweets followed a Washington Post article that claimed Mr Obama learned of Russian President Vladimir Putin’s “direct involvement” in August 2016, three months before the election.

US political expert Dr Raymond Orr from the University of Melbourne said Mr Trump’s admission is part of a strategy to “shift the evidence” away from possible collusion between him and the Russian government.

“If there’s a strategy to it, it’s to shift the evidence away from the cover-up and obstruction of the Russia investigation to something he can’t be impeached for,” Dr Orr told The New Daily.

Just out: The Obama Administration knew far in advance of November 8th about election meddling by Russia. Did nothing about it. WHY?

— Donald J. Trump (@realDonaldTrump) June 24, 2017

“Trump is much more vulnerable to collusion than he is in admission of something he wasn’t directly involved in.

“He can’t be responsible for that because he wasn’t in power at the time, but he can be responsible for a cover-up of collusion and a relationship with Russia. That’s what gets presidents impeached.”

The tweets came after Mr Trump expressed similar criticism of his predecessor in an interview with Fox News.

“Well I just heard today for the first time that Obama knew about Russia a long time before the election, and he did nothing about it,” he told Fox News on Friday.

“The CIA gave him information on Russia a long time before they even – before the election.

“To me, in other words, the question is, if he had the information, why didn’t he do something about it? He should have done something about it.”

Since the Obama Administration was told way before the 2016 Election that the Russians were meddling, why no action? Focus on them, not T!

— Donald J. Trump (@realDonaldTrump) June 24, 2017

The Washington Post article story said Mr Obama and three senior aides knew of the “intelligence bombshell” that detailed Mr Putin’s direct involvement in a cyber campaign to disrupt and discredit the US presidential race.

It said the Obama administration secretly debated dozens of options to punish Russia, but in the end settled on modest punitive measures – the expulsions of 35 diplomats and the closure of two Russian compounds in late December.

Mr Obama was reportedly concerned he would look like he had been trying to manipulate the election himself if he took action, The Post said.

But in hindsight, a former senior Obama administration official said they mishandled deliberations on Russia, and “sort of choked”.

“It is the hardest thing about my entire time in government to defend,” the paper quoted.

“I feel like we sort of choked.

“From national security people there was a sense of immediate introspection, of, ‘Wow, did we mishandle this’.”

Measures Mr Obama considered but did not put into action included cyberattacks on Russian infrastructure, the release of CIA-gathered material that might embarrass Mr Putin, and sanctions that officials said could “crater” the Russian economy.