A FIRED-UP Donald Trump threatened to retaliate if Democrats use their new powers to investigate him, promising any “warlike posture” would be met with equal force.

The pledge, a day after Republicans lost control of the House of Representatives but retained the Senate and fared better in the midterm ballot than either history or polling predicted, came during an extraordinary televised clash with reporters that saw one of Mr Trump’s most frequent media antagonists lose his White House accreditation.

In his longest solo press conference, Mr Trump spoke with journalists for 87 minutes in the East Room, in a torrid performance in which he labelled one black questioner racist, ordered others to “sit down” and called CNN political reporter Jim Acosta a “rude, terrible person”.

Last night, Mr Acosta’s White House “hard pass” or permanent media credential, was revoked, effectively barring him from access, after press secretary Sarah Huckabee Sanders said he had manhandled a White House aide who tried to take a microphone from him during the heated exchange.

“This conduct is absolutely unacceptable. It is also completely disrespectful to the reporter’s colleagues not to allow them an opportunity to ask a question,” she said in a tweeted statement.

“This is a lie,” Mr Acosta said.

Video of the exchange shows Mr Acosta does not appear to place his hands on the intern.

The White House last night released a slow motion video which shows his hand pushing down her arm as she tried to take the microphone, but it is not clear from viewing whether his hand fell or whether he was forcing her arm down.

Meanwhile, the White House revealed that Attorney-General Jeff Sessions, about whom Mr Trump has been complaining publicly for months, tendered his resignation at the request of the President.

Mr Sessions’ effective sacking was not a surprise, given Mr Trump’s displeasure with his top politician for recusing himself from the probe by Special Counsel Robert Mueller that is looking at ties between the Trump administration and Russian efforts to impact the 2016 election.

One of the earliest supporters of the Trump presidential bid, Mr Sessions was replaced by his chief of staff Matt Whitaker, who has previously criticised the Mueller investigation.

Winning the House has granted Democrats subpoena power and control of several investigative committees that have already indicated they will seek access to Mr Trump’s tax returns, business activities and campaign dealings.

But Mr Trump said the Republican-held Senate would strike back at any investigations and “waste of public money”.

“Almost from the time I announced I was going to run, they’ve been giving us this investigation fatigue,” he said.

“It’s been a long time. They got nothing. Zero. You know why? Because there is nothing.

“But they can play that game, but we can play it better. Because we have a thing called the United States Senate.”

Later in the same press conference, he got into several heated arguments with members of the White House Press Corp, at one point walking away from the lectern and appearing to compose himself before returning to re-engage.

After several back-and-forths, and being told his time to ask questions had passed, CNN reporter Jim Acosta asked: “Mr President, are you worried about indictments coming down in this investigation?”

“I’ll tell you what: CNN should be ashamed of itself having you working for them. You are a rude, terrible person. You shouldn’t be working for CNN,” Mr Trump replied, trying to direct questions to another reporter.

Acosta kept hold of the microphone and said: “I think that’s unfair”.

“You’re a very rude person,” Mr Trump said.

“The way you treat (White House Press Secretary) Sarah Huckabee is horrible. And the way you treat other people are horrible. You shouldn’t treat people that way.”

The next questioner tried to stick up for Mr Acosta, saying: “He’s a diligent reporter who busts his butt like the rest of us”.