WASHINGTON — Rob Porter, an aide to President Donald Trump, announced his resignation on Wednesday after the Daily Mail published details from his ex-wives of verbal and physical abuse.

Porter, who is serving as staff secretary, said in a statement that the “outrageous allegations are simply false.”

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

White House spokeswoman Sarah Huckabee Sanders said that his departure would not be immediate. She read his statement at the White House press briefing.

“I have always put duty to country first and treated others with respect. I am deeply grateful for the opportunity to have served in the Trump Administration and will seek to ensure a smooth transition when I leave the White House,” Porter’s statement said.

The Daily Mail posted a story on Tuesday in which Jennifer Willoughby, Porter’s second wife, recounted Porter’s “explosive anger.” The publication also posted a photo of a protective order she obtained for violating a separation agreement. His first wife, Colbie Holderness, also recounted that he was abusive and provided a photo that showed her with a black eye. She said it was a result of him punching her while they were on vacation in Italy.

Porter worked closely with White House chief of staff John Kelly, and was a key figure in controlling the flow of information to the president.

CBS News and other outlets reported that Porter did not have a full security clearance. White House spokeswoman Sarah Huckabee Sanders said that “consistent with the practice of past administrations, issues related to an individual’s suitability are reviewed through a thorough and lengthy background check process.”

“Background checks involve a complex investigation run by intelligence and law enforcement agencies,” she said. “As has always been our policy, we do not comment on security clearances. Rob Porter has been effective in his role as staff secretary. The President and Chief of Staff have full confidence in his abilities and his performance.”