Washington (CNN) President Donald Trump's tweet Wednesday calling on his attorney general, Jeff Sessions to end special counsel Robert Mueller's investigation into Russian election interference came as his lawyers continue to haggle with the special counsel about the parameters of a potential presidential interview.

On Tuesday evening and Wednesday morning, Trump's lawyers updated him by phone on the latest developments, one person familiar with the matter told CNN. That included Mueller's latest proposal to secure an interview with Trump , which was delivered on Tuesday. Trump tweeted at Sessions hours after being updated by his legal team.

Although the President has repeatedly criticized the investigation and Sessions' decision to recuse himself from overseeing it, Trump's tweet that his attorney general "should stop" the probe is notable and raises fresh questions about whether the President is attempting to obstruct justice.

"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!" the President tweeted.

..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!

People inside the White House said the burst of tweets reflected the anger Trump has aired privately for months, including about Sessions. Trump has been more frustrated since headlines about his former attorney Michael Cohen emerged last week. Aides say they're working to schedule more political rallies, partly to boost Trump's mood and distract him from the headlines about Russia.

Trump talks to supporters

Trump has heard from top allies that he should be more outspoken about Sessions, even as Trump remains wary of firing him, people familiar with the conversations say.

On Tuesday night, Trump flew back from Florida with former aides who have stoked his anger and impulses in the past: current campaign manager Brad Parscale and former campaign manager Corey Lewandowski. Earlier this summer, Parscale tweeted that Trump should fire Sessions in order to bring the Mueller probe to an end. A person on the flight says Trump spent most of his time with them in the air.

The Justice Department declined to comment on Trump's tweet Wednesday. Trump's attorney, Rudy Giuliani, attempted to walk back the tweet early Wednesday afternoon, telling CNN's Dana Bash that Trump was "expressing his opinion on his favored medium for asserting his First Amendment right of free speech. He said 'should' not 'must' and no Presidential order was issued or will be."

White House press secretary Sarah Sanders echoed that interpretation, telling reporters Trump "wants to see it come to an end as he has stated many times and we look forward to that happening."

She added, "The President is not obstructing. He's fighting back."

Although CNN has reported that several members of Mueller's team have donated to Democrats, Russia's interference in the 2016 election has also been the subject of several Republican-led congressional inquiries. Mueller is a Republican who was appointed as FBI director by President George W. Bush, and the man who tapped him as special counsel, Deputy Attorney General Rod Rosenstein, was named by Trump and is also a registered Republican.

Last year, Sessions recused himself from any investigation related to the 2016 presidential campaigns soon after it came to light that he had failed to disclose during his Senate confirmation hearing contacts with Russia's ambassador to Washington. After he stepped aside, Rosenstein appointed Mueller as special counsel to look into Russian interference, including whether any Trump campaign officials coordinated with Moscow.

Raises obstruction questions

JUST WATCHED CNN: Giuliani says Trump "was expressing his opinion" with Sessions tweet Replay More Videos ... MUST WATCH CNN: Giuliani says Trump "was expressing his opinion" with Sessions tweet 04:37

A central focus of Mueller's probe is whether Trump has obstructed justice in the Russia investigation, and Wednesday's tweet could be scrutinized by the special counsel's team. Citing three people briefed on the matter, The New York Times reported last month that Mueller is reviewing Trump's tweets as well as "negative statements" made by the President related to the attorney general and former FBI director James Comey, whom Trump abruptly fired last year.

California Rep. Adam Schiff, the top Democrat on the House Intelligence Committee, raised the question on Twitter Wednesday shortly after Trump's remark.

"The President of the United States just called on his Attorney General to put an end to an investigation in which the President, his family and campaign may be implicated," Schiff wrote. "This is an attempt to obstruct justice hiding in plain sight. America must never accept it."

Sen. Susan Collins, R-Maine, called the tweet "highly inappropriate" and dismissed the possibility that Mueller is going to be fired.

"It would be far better if the President refrained from commenting and for Mr. Mueller to continue his investigation, which so far already has 30 indictments, including Russian nationalists," she said on Capitol Hill.

Trump ratchets up attacks

JUST WATCHED Sanders: Trump tweet on Sessions is his opinion Replay More Videos ... MUST WATCH Sanders: Trump tweet on Sessions is his opinion 00:53

The President has escalated his attacks on the Mueller probe in recent days, and his tweet on Wednesday comes on the second day of former Trump campaign chairman Paul Manafort's trial, the first case Mueller's team has taken before a jury. Manafort is facing charges of bank fraud and tax evasion, though his alleged crimes occurred before he was involved with the Trump campaign.

Trump brought up Manafort by name in a second tweet on Wednesday, saying that he has worked in the past for "highly prominent and respected political leaders," and that the charges against him "have nothing to do with Collusion," which he referred to as "a Hoax!" In another tweet on Wednesday, Trump wrote, "Russian Collusion with the Trump Campaign, one of the most successful in history, is a TOTAL HOAX."

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 didn't 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

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

Trump has repeatedly denied that his campaign colluded with Russia. He has repeatedly criticized Sessions for recusing himself and CNN has previously reported that Trump pressured the attorney general on multiple occasions to overturn his recusal.