WASHINGTON -- President Donald Trump on Saturday seemed to frame the downfall of a pivotal aide accused of abusing his wives as a character assassination, adding to the tumult that has engulfed the White House, splintered the staff and imperiled chief of staff John Kelly's hold on his position.

Trump vented in a tweet that appeared to take aim at the rising #MeToo movement about sexual abuse and echoed his own denials of sexual impropriety in the face of accusations from more than a dozen women.

"Peoples lives are being shattered and destroyed by a mere allegation," "Some are true and some are false. Some are old and some are new. There is no recovery for someone falsely accused - life and career are gone. Is there no such thing any longer as Due Process?"

His response also reflected his growing discontent with Kelly, once hailed for bringing discipline to the West Wing but recently at the centre of his own controversies.

The president has fumed that Kelly was too slow in bringing the allegations against staff secretary Rob Porter to his attention. That has added to Trump's frustrations about the chief of staff's attempts to control him and Kelly's recent inflammatory comments about immigrants, according to two people who speak to the president regularly but are not authorized to publicly discuss private conversations.

The two strong-willed men have clashed and Trump has begun floating possible names for a future chief of staff in conversations with outside advisers, according to three people with knowledge of the conversations. Among the names being considered: Budget Director Mick Mulvaney, House Majority Leader Kevin McCarthy, Rep. Mark Meadows and CIA Director Mike Pompeo.

But there was no sign that a move was imminent, according to the people with knowledge of the conversations. Trump is known to frequently poll his advisers about the performance of senior staff and is often reluctant to actually fire aides.

As the aftershocks of the accusations against Porter reverberated for a fifth day, Trump stayed out of sight on a rainy Saturday in Washington and tweeted along while watching Fox News shows. Most West Wing offices remained dark.

Kelly has indicated he would step aside if he lost the faith of the president. But he has not offered to resign, according to a White House official who was not authorized to discuss personnel matters publicly and spoke Friday on condition of anonymity.

But Kelly's hold on his post seemed the shakiest since he took the job in July, in part because several West Wing aides have had their faith shaken by his handling of the Porter accusations. At a senior staff meeting on Friday, Kelly tried to push his own timeline concerning Porter. Some aides in that meeting privately questioned Kelly's account, thinking his version of events was self-serving, according to one official with knowledge of the meeting but not authorized to discuss it publicly.

Kelly has said he found out only Tuesday night that the accusations against Porter were true and he was gone immediately. That clashes with the events of Tuesday night, when the White House released a statement of support for Porter from Kelly, who had initially urged his right-hand-man to remain in his post. The chief of staff said Friday that the decision was made before photos of one of Porter's ex-wives with a black eye were published.

Other White House officials have said it was the release of the photos Wednesday morning that sealed Porter's fate. The staff secretary resigned later Wednesday.

On Friday, a second White House staffer, speechwriter David Sorensen, resigned as a result of abuse allegations. Sorensen worked for the Council on Environmental Quality, which is part of the Executive Office of the President.

Many White House senior staff members remained stunned by the accusations against Porter, a well-liked and seemingly mild-mannered graduate of Harvard and Oxford. When the allegations first emerged against Porter, who downplayed the claims from two ex-wives, a number of senior aides rallied around him, and the White House acknowledged that personal relationships may have played a role in their response.

Communications Director Hope Hicks, who was dating the staff secretary, helped draft the original statements defending him, according to three current and former White House officials. Deputy White House press secretary Raj Shah said Hicks later "recused" herself from some aspects of the matter.

It was a rare moment in the spotlight for Hicks, Trump's longest-serving aide who is usually content to remain in the background. Hicks has become one of Trump's closest confidants, and while the president has groused about her involvement in the Porter flareup, he had not suggested ousting her, according to the two people familiar with his private discussions.

The fallout from the Porter resignation also cast a spotlight on White House counsel Don McGahn, who was apprised of at least some of the accusations about the staff secretary at least four times, including as early as January 2017.

Kelly, meanwhile, told reporters the only other indication he had that something could be wrong came in November, when he got an update on pending background investigations and learned "there was some things that needed to be looked into. And literally that was it."

Porter's departure, along with Kelly under fire, could deprive the West Wing of some of its steadier hands and worried some staffers that the sense of order that been installed in recent months could evaporate.

The president's tweet Saturday came a day after he set off a firestorm when he wished Porter well in his future endeavours and made no mention of his alleged victims. "He said very strongly yesterday that he's innocent," Trump said.

Routinely, Trump has accepted claims of innocence from men facing similar allegations, including Fox News head Roger Ailes, anchor Bill O'Reilly and former Alabama Senate candidate Roy Moore, who was accused of inappropriate contact with teenage girls.

Trump's comments were a sharp contrast to those of Vice-President Mike Pence, who told NBC's Lester Holt on Friday "there's no tolerance in this White House and no place in America for domestic abuse."

Pence said in an interview in South Korea that he was "appalled" by the allegations and that he would look into the matter when he got back to Washington.

Meanwhile, a number of Democrats denounced Trump's comments about Porter and his lack of empathy for the women who alleged abuse.

"That's like saying that axe murderer out there, he's a great painter," said former Vice-President Joe Biden. "Is there any other crime -- and it's a crime --where there would be an explanation that the reason why we shouldn't pay attention to the transgression is because they're good at something?"

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Associated Press writers Jill Colvin, Juliet Linderman and Zeke Miller contributed to this report.