President TrumpDonald John TrumpGOP lawmakers preparing to vote on bill allowing migrant children to be detained longer than 20 days: report Wasserman Schultz: Infants separated from their parents are in Florida immigrant shelters Ex-White House ethics chief: Sarah Sanders tweet violates ethics laws MORE is reportedly frustrated with chief of staff John KellyJohn Francis KellyMORE over his handling of abuse allegations against former White House staff secretary Rob Porter and has started considering replacements. 

Sources told NBC News that Trump is angry over Kelly's statements on Porter, specifically his initial defense of the top aide following allegations of domestic abuse. According to sources, Trump has openly talked about replacing Kelly. 

NBC News reports that Office of Management and Budget Director Mick MulvaneyJohn (Mick) Michael MulvaneyMulvaney aims to cement CFPB legacy by ensuring successor's confirmation On The Money — Sponsored by Prudential — Trump floats tariffs on European cars | Nikki Haley slams UN report on US poverty | Will tax law help GOP? It's a mystery Democrat says he recommended Trump's budget director for his job MORE is one of the names Trump has floated to replace his chief of staff.

Porter resigned Wednesday after reports surfaced of allegations of physical and verbal abuse by his two ex-wives. 

Kelly on Tuesday defended Porter as a "man of true integrity and honor" after reports of the alleged abuse first emerged, but later said he was "shocked" by the allegations and insisted that there is "no place for domestic violence in our society."

The chief of staff's backtracking, however, hasn't been enough to stave off backlash. 

Kelly has faced scrutiny over his decision to keep Porter on staff despite knowing about the allegations. The FBI reportedly informed the White House of Porter's past behavior while conducting a background check. Porter continued to work at the White House months after officials first learned of the allegations against him, according to reports, and worked in the West Wing without a national security clearance.

Despite Trump's frustration with Kelly over the situation, a source told NBC that he is unlikely to fire his chief of staff "because there's too much drama." 

The Trump White House has seen significant turnover of top-ranking officials during the president's first year in office, including chief strategist Stephen Bannon and press secretary Sean SpicerSean Michael SpicerFox's Guilfoyle: Women in Trump administration 'dealt an unfair hand' by 'dishonest' media Trump needles ABC News over false Manafort graphic The Hill's 12:30 Report - Sponsored by Delta Air Lines - Trump says he will sign 'something' to end family separations MORE