U.S. President Donald Trump, not one to shy away from a Twitter fight, intensified an online battle with senior White House adviser Kellyanne Conway's husband on Wednesday, calling George Conway a "husband from hell."

Of all the brawls Trump has waded into, his back-and-forth with lawyer George Conway has been one of the more eyebrow-raising in Washington.

Trump relied heavily on Kellyanne Conway, a longtime Republican pollster and strategist, to help steer his presidential campaign to victory in 2016. She is a trusted member of his White House inner circle.

In a tweet, Trump wrote that George Conway is upset that he did not get a job in the Trump administration.

But the Washington Post quoted Conway – a litigation specialist with New York-based law firm Wachtell, Lipton, Rosen & Katz – as saying he actually turned down an offer to head the Justice Department's Civil Division.

In a morning tweet, Trump wrote, "George Conway, often referred to as Mr. Kellyanne Conway by those who know him, is VERY jealous of his wife's success & angry that I, with her help, didn't give him the job he so desperately wanted. I barely know him but just take a look, a stone cold LOSER & husband from hell!"

Trump has been expressing his irritation with George Conway in response to the lawyer's recent suggestion that the president was suffering from a mental condition such as narcissistic personality disorder and is unfit to serve as president.

Conway suggested the diagnosis in response to a torrent of tweets unleashed by Trump last weekend laying bare his grievances with, among other topics, Fox News Channel's weekend anchors and the late Senator John McCain.

Conway on Wednesday posted a brief response on Twitter commenting on Trump's latest tirade: "You. Are. Nuts."

(Cover: White House Counselor Kellyanne Conway and her husband George Conway arrive for a candlelight dinner at Union Station on the eve of the 58th Presidential Inauguration in Washington, U.S., January 19, 2017. /VCG)