Key Trump aide resigns as two ex-wives allege abuse

White House Press Secretary Sarah Sanders told reporters Portman has resigned, a day after the UK-based Daily Mail newspaper published allegations of his two ex-wives, Colbie Holderness and Jennifer Willoughby, accusing him of domestic violence.

Portman, 40, has, however, denied the allegations.

"These outrageous allegations are simply false. I took the photos given to the media nearly 15 years ago and the reality behind them is nowhere close to what is being described," Portman said.

"I have been transparent and truthful about these vile claims, but I will not further engage publicly with a coordinated smear campaign," he said in a statement.

As staff secretary, Porter's responsibility was mainly in the flow of paper that crossed Trump's desk, including the wave of executive orders and actions that Trump inked during the first months of his tenure.

A lawyer, Porter also participated in the process of legally vetting the myriad documents that require the President's signature, CNN reported.

Porter's first spouse, Holderness, said the White House aide had been verbally and physically abusive.

Holderness, a US government analyst, said Porter had kicked her on their 2003 honeymoon in the Canary Islands.

She also alleged he punched her in the face while they were on holiday a couple of years later in Florence, Italy.

Holderness supplied a photo of herself with a black eye to the media.

Willoughby, a motivational speaker, told the Daily Mail she was married to Porter from 2009-13.

She said she filed a protective order against him in June 2010 after he allegedly punched the glass of the door at their Alexandria, Virginia, home.

Willoughby told the Washington Post: "He has never faced repercussions that forced him to confront his issues.

"I care about him and want what's best for him, but that doesn't necessarily mean him keeping his job because he needs to face these underlying issues."

Porter's resignation has turned out to be another uncomfortable situation for a White House that has been largely out of step with the #MeToo movement that has swept the country.

Trump, given the range of sexual harassment and assault allegations against him, has long struggled to respond to the nationwide focus on the mistreatment against women, CNN noted.

During the election, at least 15 women accused Trump of ranging from sexual harassment and sexual assault to lewd behaviour around women.

But the White House has dismissed all the allegations against him as old news that had been litigated during the 2016 campaign.