Because it was a closed briefing, it's unclear exactly how Rosenstein described how he knew Trump would fire Comey. Trump wrote, misspelling the word counsel as he referred to former President Barack Obama and former presidential candidate Hillary Clinton.
Senate Minority Whip Dick Durbin said Rosenstein did confirm the Department of Justice did not seek the approval of the White House when selecting Mueller to take over the investigation but remained mum on the details as to why Comey was sacked.
Then Trump admitted he had been considering firing Comey for months.
Mr Trump has been under fire since news emerged this week that he had shared secrets with the Russians and allegedly tried to stop former Federal Bureau of Investigation director James Comey from investigating his former adviser Michael Flynn.
But Rosenstein did not disclose further details about the memo he wrote, according to House members on Friday.
But it is not Trump's right to choose who should get involved in the investigation into "any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump", as well as other matters that "may arise directly from the investigation".
Meanwhile, Leahy is also requesting more information on Trump's business ties across the world, which could potentially violate the emoluments clause of the U.S. Constitution. The Trump-Russia probe has been a hot topic practically since the presidential campaigns were still running. A selloff in USA stocks looked set to extend into its second day on Thursday. He also told network anchors at the White House on Thursday that appointing a special counsel "hurts the country".More news: Blood tests to resume at NHS cyber attack hospitals from tomorrow
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Some senators say they're anxious the Justice Department's appointment of a special counsel to oversee the Russian Federation investigation could effectively halt congressional probes into the matter.
"We still have questions and we'll be outlining those in the days ahead", Casey said.
"You're pretty well knocked out of the game", he said about the ongoing high-profile congressional probes, "and that's probably the way it should be". "It seems to be now to be considered a criminal investigation". Another Republican congressman, Carlos Curbelo, said if any wrongdoing was uncovered, "Those people should be held accountable". "I am not on a witch hunt. I am on a fact-finding mission", he said on CNN.
Once the briefing concluded, Missouri Sen. "This won't be a witch hunt", he said on CNN.
Sen. Dick Durbin, D-Illinois, said Rosenstein told the full Senate he was not pressured into writing the memo, but did so after learning of the president's decision to fire Comey.
Cornyn said Rosenstein asked for "a single point of contact so that we can coordinate and facilitate this".