WASHINGTON — President Donald Trump fired Veterans Affairs Secretary David Shulkin on Wednesday in the wake of a bruising ethics scandal and a mounting rebellion within the agency.

Shulkin is the second Cabinet secretary to depart over controversies involving expensive travel, following former Health and Human Services Secretary Tom Price’s resignation last September.

Trump is nominating Rear Admiral Ronny Jackson to succeed Shulkin, a former Obama administration official and the first non-veteran ever to head the VA. Jackson has served since 2013 as the Physician to the President, and gained a national profile earlier this year for holding a sweeping press conference on the president’s health.

Trump has selected Robert Wilkie, the Under Secretary of Defense for Personnel and Readiness, to serve as the acting head of the VA. It is government’s second largest department, responsible for 9 million military veterans in more than 1,700 government-run health facilities. The selection of Wilkie bypasses VA Deputy Secretary Tom Bowman, who has come under criticism for being too moderate to push Trump’s agenda of fixing veterans’ care.

Shulkin had continued to insist he had the full confidence of the White House amid continuing investigations over his travel and leadership of the department. He had agreed to reimburse the government more than $4,000 after the VA’s internal watchdog concluded last month that he had improperly accepted Wimbledon tennis tickets and that his then-chief of staff had doctored emails to justify his wife traveling to Europe with him at taxpayer expense.