With news reports that the Special Counsel investigating election interference in 2016 by Russia is looking at possible obstruction of justice by President Donald Trump, Mr. Trump expressed frustration Thursday and Friday at the prospect of that review, again taking to Twitter to denounce the probe as a "witch hunt," and complaining that Hillary Clinton should be the subject of a Russia-related investigation, not him.

"Why is that Hillary Clintons family and Dems dealings with Russia are not looked at, but my non-dealings are?" the President tweeted in the afternoon, as he said the Clintons deserved an obstruction of justice probe.

The President began his day by saying there was "zero proof" of any links between Russia and members of his campaign.

It was six days ago that Mr. Trump proclaimed that he had been vindicated by the Congressional testimony of former FBI Director James Comey, who said he had told the President several times that he was not under investigation related to Russian election interference.

But Senate investigators continue to press other top officials of the U.S. Intelligence Community for details about their own recent contacts with President Trump, which have been reported to include appeals to help end the FBI probe of Russian election meddling.

On Monday night, National Security Agency chief Michael Rogers met with the Senate Intelligence Committee about those matters; Director of National Intelligence Dan Coats was doing the same around the time of the President's afternoon tweets.

Mr. Trump's morning tweets included what seemed like a jab at former FBI Director Robert Mueller, the new Special Counsel for the Russia probe, as he said the investigation was being "led by some very bad and conflicted people!"

But at the White House today, spokeswoman Sarah Huckabee Sanders acknowledged to reporters that Mueller had been at the White House - just the day before he was appointed as Special Counsel, as she said it was a job interview.

"In terms of specific job, whether it was acting or permanent, I'm not sure, and I'd have to check and get back to you," Sanders told reporters in an off-camera briefing.

While most Republicans in Congress said little about Mr. Trump's criticism of Mueller, other supporters echoed the President's concerns.

"Mueller is setting up a dragnet of obstruction, financial questions and every aspect of Trump's life and his associates lives," said former House Speaker Newt Gingrich, who labeled it "very dangerous."

On Friday morning, the President was still aggravated, and showed that once more on Twitter: