President Donald Trump says it’s “sad” that seven months of investigations and hearings into possible links between his campaign and Russia have been fruitless.

The president tweeted Friday, “After 7 months of investigations & committee hearings about my ‘collusion with the Russians,’ nobody has been able to show any proof. Sad!”

His comments follow revelations that special counsel Robert Mueller is examining whether Trump obstructed justice by firing FBI Director James Comey. Mueller is now leading the investigation into whether Russia interfered in the 2016 presidential election.

Trump lashed out at the investigators driving the Russia investigation as “very bad and conflicted people,” responding angrily to reports that the special counsel is looking into whether Trump obstructed justice.

In a series of statements on Twitter Thursday, Trump called special counsel Robert Mueller’s investigation into Russian interference in the 2016 campaign a “WITCH HUNT” based on the “phony” premise of possible collusion between Russia and a cadre of Trump campaign associates.

The president complained the probe is unfair and wondered why his defeated Democratic opponent wasn’t getting the same scrutiny.

“Why is that Hillary Clintons family and Dems dealings with Russia are not looked at, but my non-dealings are?” he asked.

After 7 months of investigations & committee hearings about my "collusion with the Russians," nobody has been able to show any proof. Sad!

— Donald J. Trump (@realDonaldTrump) June 16, 2017

The Fake News Media hates when I use what has turned out to be my very powerful Social Media – over 100 million people! I can go around them

— Donald J. Trump (@realDonaldTrump) June 16, 2017

Despite the phony Witch Hunt going on in America, the economic & jobs numbers are great. Regulations way down, jobs and enthusiasm way up!

— Donald J. Trump (@realDonaldTrump) June 16, 2017

“They made up a phony collusion with the Russians story, found zero proof, so now they go for obstruction of justice on the phony story. Nice,” Trump wrote in his first tweet. “You are witnessing the single greatest WITCH HUNT in American political history – led by some very bad and conflicted people! #MAGA.”

The Twitter attacks came as Vice President Mike Pence hired a personal lawyer to represent him in the intensifying investigation. Pence’s office confirmed he had retained Richard Cullen, a former Virginia attorney general and U.S. attorney for the Eastern District of Virginia, to assist “in responding to inquiries” from Mueller.

They made up a phony collusion with the Russians story, found zero proof, so now they go for obstruction of justice on the phony story. Nice

— Donald J. Trump (@realDonaldTrump) June 15, 2017

You are witnessing the single greatest WITCH HUNT in American political history – led by some very bad and conflicted people! #MAGA

— Donald J. Trump (@realDonaldTrump) June 15, 2017

Why is that Hillary Clintons family and Dems dealings with Russia are not looked at, but my non-dealings are?

— Donald J. Trump (@realDonaldTrump) June 15, 2017

Mueller investigation appeared to be reaching a broadening circle of current and former officials. The Washington Post reported Wednesday that the investigators were looking into possible obstruction of justice. The newspaper noted Mueller had requested interviews with CIA Director Dan Coats, National Security Agency chief Michael Rogers and Richard Ledgett, the former NSA deputy director. Recent news reports have suggested Trump sought all three officials’ help in pressuring FBI Director James Comey to drop his investigation into former National Security Adviser Mike Flynn.

Comey testified last week that he also felt pressured to drop the Flynn probe. Comey said he believes Trump ultimately fired him “because of the Russia investigation.”

Coats met behind closed doors for more than three hours Thursday with the Senate intelligence committee, which is conducting a separate investigation into Russian interference in the 2016 election.

Trump’s Twitter response followed days of intensifying criticism of Mueller from some conservatives who have charged the former FBI director and his team with political bias and have claimed his relationship to Comey and an earlier meeting with Trump amount to conflicts of interest.

A close Trump associate said this week the president was considering firing Mueller, although the White House later denied it.

Crooked H destroyed phones w/ hammer, 'bleached' emails, & had husband meet w/AG days before she was cleared- & they talk about obstruction?

— Donald J. Trump (@realDonaldTrump) June 15, 2017

(AP)