WASHINGTON (Reuters) - U.S. President Trump on Friday lashed out at Special Counsel Robert Mueller’s investigation into possible collusion between Russia and Trump’s 2016 election campaign, and suggested Deputy Attorney General Rod Rosenstein had a conflict of interest without offering any evidence.

Trump’s series of early morning tweets came ahead of the expected filing of legal documents on Friday that could shed more light on how two of Trump’s closest former aides have helped or hindered Mueller’s Russia probe.

Representatives for the U.S. Department of Justice declined to comment on the Trump tweets.

In a later tweet, Trump said his lawyer, former New York City Mayor Rudy Giuliani, would release a response to any conclusions Mueller reports.

“It has been incorrectly reported that Rudy Giuliani and others will not be doing a counter to the Mueller Report. That is Fake News. Already 87 pages done, but obviously cannot complete until we see the final Witch Hunt Report,” he wrote.

Trump frequently derides the Mueller probe as a “witch hunt.” Rosenstein had been tasked with overseeing the investigation, though that role became unclear after Trump appointed Matthew Whitaker as acting attorney general.