US President Donald Trump has called on his Attorney General Jeff Sessions to end a federal investigation into Russian interference in the 2016 presidential election and whether his campaign cooperated with Moscow.

The Republican president, who has long complained about the criminal probe into his White House victory, said the idea that his campaign worked with Moscow was a “TOTAL HOAX” in a series of tweets aimed at undermining the integrity of Special Counsel Robert Mueller’s investigation.

In what appeared to be his most direct call for shutting down the probe, Mr Trump wrote on Twitter: “This is a terrible situation and Attorney General Jeff Sessions should stop this Rigged Witch Hunt right now, before it continues to stain our country any further.”

“Bob Mueller is totally conflicted,” Mr Trump continued but provided no evidence that the team led by Mr Mueller, a Republican appointed by Republicans, is biased against him.

The White House later insisted the tweet was not an order to Mr Sessions and that Trump was expressing his frustration with the length of the probe.

Russian Collusion with the Trump Campaign, one of the most successful in history, is a TOTAL HOAX. The Democrats paid for the phony and discredited Dossier which was, along with Comey, McCabe, Strzok and his lover, the lovely Lisa Page, used to begin the Witch Hunt. Disgraceful!

— Donald J. Trump (@realDonaldTrump) August 1, 2018

The first trial arising from the probe into Russia’s role in the election, began on Tuesday in Alexandria, Virginia. Trump’s former campaign chairman, Paul Manafort, faces 18 counts of bank and tax fraud charges.

A Justice Department spokeswoman said the department had no immediate comment on Trump’s tweet about ending Mr Mueller’s probe.
“It’s not an order. It’s the president’s opinion,” White House spokeswoman Sarah Sanders told a news briefing when asked about the tweet.

She denied that Trump was obstructing the probe and said: “He’s fighting back.”

Mr Trump’s personal lawyer, Rudy Giuliani, said that in his tweet Mr Trump was expressing an opinion long espoused by his team.

“We have been saying for months that it is time to bring this inquiry to an end. The president has expressed the same opinion,” Mr Giuliani told Reuters.

Looking back on history, who was treated worse, Alfonse Capone, legendary mob boss, killer and “Public Enemy Number One,” or Paul Manafort, political operative & Reagan/Dole darling, now serving solitary confinement – although convicted of nothing? Where is the Russian Collusion?

— Donald J. Trump (@realDonaldTrump) August 1, 2018

The Republican president has steadily attacked Mr Sessions for recusing himself from the Russia probe in March 2017.

Mr Sessions cited his role as a senior adviser to Mr Trump’s presidential campaign and appointed Deputy Attorney General Rod Rosenstein to oversee the investigation.

Mr Rosenstein in turn appointed Mr Mueller and is the person with the authority to fire him. An element of Mr Mueller’s investigation includes whether Mr Trump or anyone in the campaign tried to obstruct justice.

Democratic lawmakers said Wednesday’s tweet was an effort by Mr Trump to end the probe.

“It’s clear to me he’s very worried about it and he wants to prevent it any way he can,” said Senator Dianne Feinstein, the top Democrat on the Judiciary Committee.

Legal analysts said Wednesday’s tweet alone was not enough to bring an obstruction of justice charge but it could be used to establish a pattern of conduct revealing Mr Trump’s intentions.

“It is a piece of evidence. It is part and parcel with the other 94 things the man has done that show obstruction of justice,” Paul Rosenzweig, a former prosecutor who was part of a team that investigated President Bill Clinton, said.

The New York Times reported last week the Mueller team was examining negative tweets and statements by Mr Trump about Mr Sessions and former FBI Director James Comey.

-AAP