Donald Trump has called on the attorney general to end special counsel Robert Mueller's investigation into possible Russian collusion during the 2016 election campaign.
The US president's comments after a day after his former campaign chairman Paul Manafort went on trial in Alexandria, Virginia.
He faces 18 counts of bank and tax fraud charges.
Mr Trump unleashed a Twitter tirade on Wednesday as he sought to defend himself and Mr Manafort, and criticised a probe into whether his campaign team worked with Russia to try and sway the result of the election two years ago.
In one tweet he said Attorney General Jeff Sessions "should stop this Rigged Witch Hunt right now, before it continues to stain our country any further".
..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, and his 17 Angry Democrats that are doing his dirty work are a disgrace to USA!
— Donald J. Trump (@realDonaldTrump) August 1, 2018
In a reference to the special prosecutor who is heading-up the Russia probe, the president added: "Bob Mueller is totally conflicted, and his 17 Angry Democracts that are doing his dirty work are a disgrace to the USA!"
The president's calls for the investigation to end come after he tweeted that "collusion is not a crime" ahead of Mr Manafort's trial.
The relationship between Mr Trump and Mr Sessions has been strained for more than a year, after the attorney general recused himself from the probe relating to the 2016 election.
He cited the fact he was a senior adviser to Mr Trump's presidential campaign, and appointed Deputy Attorney General Rod Rosenstein to oversee the investigation instead.
Mr Rosenstein is the one who appointed Mr Mueller and has the authority to fire him.
The special prosecutor is also investigating a potential obstruction of justice by the president.
Sky News' US correspondent Mark Austin said: "(Mr Trump) is consistently trying to undermine his attorney general and the Mueller investigation.
"He's loathed Jeff Sessions ever since he recused himself from the whole issue of Russia meddling."
He added: "There are two things specifically that are worrying Donald Trump at the moment.
Paul Manafort worked for Ronald Reagan, Bob Dole and many other highly prominent and respected political leaders. He worked for me for a very short time. Why didnt government tell me that he was under investigation. These old charges have nothing to do with Collusion – a Hoax!
— Donald J. Trump (@realDonaldTrump) August 1, 2018
"One is his former fixer and lawyer of 10 years Michael Cohen, who looks as if he's going to co-operate with the authorities.
"What is Michael Cohen going to tell them?"
Mr Austin added: "The second is Paul Manafort the former campaign chairman.
"He is on trial on financial charges to do with bank fraud and tax evasion and money laundering, but he has very well established connections to Russia."
Roughly two hours after calling on Mr Sessions to end the probe, the president tweeted out a passionate defence of Mr Manafort.
Spelling the famous gangster Alphonse Capone's name wrong, he wrote: "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 – altough convicted of nothing?
"Where is the Russian collusion?"
Mr Manafort's charges stem from his consulting work in the Ukraine, in which he allegedly received millions of dollars that he failed to report to the US government.
The president has defended his former campaign chairman whilst also seeking distance himself from him, he said: "He worked for me for a very short time."
Mr Manafort's involvement in the Trump campaign spanned six months and he led efforts to secure the Republican nomination for Trump 2016.
The US president has said the charges against Mr Manafort "have nothing to do with collusion".
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
Mr Trump has called claims of collusion "a hoax!".
The president quoted a Washington Post article on Wednesday in order to support his claim that his campaign didn't collude with Russia.
He wrote: "We have already have a smoking gun about a campaign getting dirt on their opponent, it was Hillary Clinton.
"How is it OK for Hillary Clinton to proactively seek dirt from the Russians by the Trump campaign met at the Russians request and that is bad?"
More from US
A US justice department spokeswoman said the department had no immediate comment on Mr Trump's tweet about ending Mr Mueller's probe.
Intelligence agencies in the US have concluded that Moscow meddled in the 2016 presidential campaign to try to tip the vote in Mr Trump's favour.
Donald Trump has called on the attorney general to end special counsel Robert Mueller's investigation into possible Russian collusion during the 2016 election campaign.
The US president's comments after a day after his former campaign chairman Paul Manafort went on trial in Alexandria, Virginia.
He faces 18 counts of bank and tax fraud charges.
Mr Trump unleashed a Twitter tirade on Wednesday as he sought to defend himself and Mr Manafort, and criticised a probe into whether his campaign team worked with Russia to try and sway the result of the election two years ago.
In one tweet he said Attorney General Jeff Sessions "should stop this Rigged Witch Hunt right now, before it continues to stain our country any further".
..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, and his 17 Angry Democrats that are doing his dirty work are a disgrace to USA!
— Donald J. Trump (@realDonaldTrump) August 1, 2018
In a reference to the special prosecutor who is heading-up the Russia probe, the president added: "Bob Mueller is totally conflicted, and his 17 Angry Democracts that are doing his dirty work are a disgrace to the USA!"
The president's calls for the investigation to end come after he tweeted that "collusion is not a crime" ahead of Mr Manafort's trial.
The relationship between Mr Trump and Mr Sessions has been strained for more than a year, after the attorney general recused himself from the probe relating to the 2016 election.
He cited the fact he was a senior adviser to Mr Trump's presidential campaign, and appointed Deputy Attorney General Rod Rosenstein to oversee the investigation instead.
Mr Rosenstein is the one who appointed Mr Mueller and has the authority to fire him.
The special prosecutor is also investigating a potential obstruction of justice by the president.
Sky News' US correspondent Mark Austin said: "(Mr Trump) is consistently trying to undermine his attorney general and the Mueller investigation.
"He's loathed Jeff Sessions ever since he recused himself from the whole issue of Russia meddling."
He added: "There are two things specifically that are worrying Donald Trump at the moment.
Paul Manafort worked for Ronald Reagan, Bob Dole and many other highly prominent and respected political leaders. He worked for me for a very short time. Why didnt government tell me that he was under investigation. These old charges have nothing to do with Collusion – a Hoax!
— Donald J. Trump (@realDonaldTrump) August 1, 2018
"One is his former fixer and lawyer of 10 years Michael Cohen, who looks as if he's going to co-operate with the authorities.
"What is Michael Cohen going to tell them?"
Mr Austin added: "The second is Paul Manafort the former campaign chairman.
"He is on trial on financial charges to do with bank fraud and tax evasion and money laundering, but he has very well established connections to Russia."
Roughly two hours after calling on Mr Sessions to end the probe, the president tweeted out a passionate defence of Mr Manafort.
Spelling the famous gangster Alphonse Capone's name wrong, he wrote: "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 – altough convicted of nothing?
"Where is the Russian collusion?"
Mr Manafort's charges stem from his consulting work in the Ukraine, in which he allegedly received millions of dollars that he failed to report to the US government.
The president has defended his former campaign chairman whilst also seeking distance himself from him, he said: "He worked for me for a very short time."
Mr Manafort's involvement in the Trump campaign spanned six months and he led efforts to secure the Republican nomination for Trump 2016.
The US president has said the charges against Mr Manafort "have nothing to do with collusion".
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
Mr Trump has called claims of collusion "a hoax!".
The president quoted a Washington Post article on Wednesday in order to support his claim that his campaign didn't collude with Russia.
He wrote: "We have already have a smoking gun about a campaign getting dirt on their opponent, it was Hillary Clinton.
"How is it OK for Hillary Clinton to proactively seek dirt from the Russians by the Trump campaign met at the Russians request and that is bad?"
More from US
A US justice department spokeswoman said the department had no immediate comment on Mr Trump's tweet about ending Mr Mueller's probe.
Intelligence agencies in the US have concluded that Moscow meddled in the 2016 presidential campaign to try to tip the vote in Mr Trump's favour.
