Rosenstein didn't provide specific examples of what he might've been referring to.
Part of the revelations surrounding the Russian Federation investigation and the firing of Comey has been that Trump repeatedly pushed top intelligence officials to say in public that Trump was not personally under investigation and that there was no evidence of collusion between his campaign and Russian Federation in its interference in the 2016 election.
The FBI will not release memos written by former director James Comey on his interactions with President Trump because they're part of a "pending or prospective law enforcement proceeding". "Witch Hunt", Trump wrote on Twitter.
The president's anger appears to be directed at Acting Attorney General Rod Rosenstein who wrote a letter recommending Comey's termination.
Trump advisers and confidants describe the president as increasingly angry over the Russian Federation investigation, yelling at television sets in the White House carrying coverage and insisting he is the target of a conspiracy to discredit - and potentially end - his presidency.
The President complained the probe was unfair and wondered why his defeated Democratic opponent was not getting the same scrutiny.
Trump has described these reports as "fake news" and the investigations as a "witch hunt". Mueller also has expansive powers to investigate any matters that develop from his initial investigation.
Sources told ABC News that Rosenstein raised the possibility of his own recusal during a meeting with Associate Attorney General Rachel Brand, who's next in line at the Department of Justice after Rosenstein.
Deputy Attorney-General Rod Rosenstein submitted a widely circulated memo to the President last month raising concerns over Mr. Comey's performance, but Mr. Trump later asserted that he had already made the decision himself to fire Mr. Comey.
He had written a memorandum to US Attorney General Jeff Sessions, criticising Mr Comey about the way in which he handled the Russian Federation investigation.
A Trump confidant said this week the President had considered firing Mr Mueller.
It's yet another tweet that's unleashed intense media speculation... a presidential post of less than 140 characters. The president has long vehemently denied any collusion with Moscow. The White House denies any collusion.
Trump kept up his criticism of the investigations in a series of tweets on Friday.
Mr Rosenstein has previously said that "if anything that I did winds up being relevant to his investigation then, as Director Mueller and I discussed, if there's a need from me to recuse, I will".
Following several media outlets, including CNN, BuzzFeed and the Times sought the memos under the Freedom of Information Act. The transition, a nonprofit structurally separate from the Trump campaign, continues to operate with a small staff.
Trump's tweet comes less than a day after a unusual statement from a senior official in his administration.
There is also no rule barring such donations, said David Alan Sklansky, a criminal procedure professor at Stanford University.