Navy Rear Adm. Ronny Jackson said Thursday he is withdrawing from consideration as President Trump's nominee to be the next secretary of the Department of Veterans Affairs amid a barrage of allegations of prior misconduct.

"Unfortunately, because of how Washington works, these false allegations have become a distraction for this President and the important issue we must be addressing — how we give the best care to our nation's heroes," Jackson said in a statement released by the White House on Thursday morning.

Jackson said he expected "tough questions" about his qualifications for the VA, "but I did not expect to have to dignify baseless and anonymous attacks on my character and integrity."

Trump told Fox News that Jackson's decision did not surprise him — "I saw where this was going" — and said "it's a disgrace" the way his nominees have been treated, including "Doc Ronny."

Jackson's nomination lasted less than a month as he came under withering criticism, first for a lack of management experience, and then this week, for accusations by colleagues that he improperly dished out opioids, drank on the job and fostered a hostile work environment at the White House medical office where he is physician to the president.

US President Donald Trump (C) and his White House physician Dr. Ronny Jackson (L) listen as US Secretary of Veterans Affairs David J. Shulkin speaks about new technology used by the Department of Veterans Affairs on August 3, 2017 in Washington, DC.
US President Donald Trump (C) and his White House physician Dr. Ronny Jackson (L) listen as US Secretary of Veterans Affairs David J. Shulkin speaks about new technology used by the Department of Veterans Affairs on August 3, 2017 in Washington, DC.
BRENDAN SMIALOWSKI/AFP/Getty Images

Those charges came on top of previous, independent investigations in 2012 and 2013 that found he engaged in "unprofessional behaviors" that contributed to a “toxic” workplace and recommended he "hone his self-awareness" of behaviors that gave staff the impression they were "purely politically driven for his self-advancement.”

White House Press Secretary Sarah Sanders had defended Jackson on Wednesday, saying his record was "impeccable" as a White House doctor, but she also said White House officials were reviewing the latest allegations, which were uncovered during a Senate investigation.

In his statement of withdrawal, Jackson called the allegations against him "completely false and fabricated." He added: "If they had any merit, I would not have been selected, promoted and entrusted to serve in such a sensitive and important role as physician to three presidents over the past 12 years."

Jackson, 50, started work as a White House doctor in 2006, was promoted to director of the White House Medical Unit in 2011 and became physician to the president in 2013. Both President Barack Obama and Trump gave him glowing performance reviews, according to portions of the reviews released by the White House.

After examining Trump earlier this year, Jackson proclaimed him to be in “excellent” health and said he had “incredibly good genes.”

The president announced his intent to nominate him to lead the VA in a tweet March 28, the same day he fired former secretary David Shulkin, also via tweet.

On Tuesday, Trump ripped senators for aggressively vetting Jackson and said he personally wouldn't endure it. He said he would leave the decision up to Jackson about whether to continue in the process.

During his interview on Fox & Friends, Trump focused his criticism on Sen. Jon Tester, D-Mont., who spoke publicly about the allegations against Jackson. Noting that Tester faces re-election this year, Trump said the claims against the VA nominee are "going to cause a lot of problems 'in his state."

But lawmakers on Capitol Hill criticized the White House for failing to adequately investigate Jackson before forwarding his nomination to the Senate.

Tester on Thursday said it is his "Constitutional responsibility to make sure the veterans of this nation get a strong, thoroughly vetted leader who will fight for them."

Some veterans' groups also faulted the administration and said veterans are suffering the consequences. AMVETS, which represents more than 250,000 veterans, said Trump shouldn't have fired Shulkin in the first place, and Jackson's short-lived, bumpy nomination represents "the latest in a chain of unforced errors for which veterans are continuing to pay the price.”

“Veterans are losing six different ways right now, from all directions, and it’s discouragingly unclear why this keeps happening or what might make it stop," AMVETS Executive Director Joe Chenelly said.

“This painful and tumultuous chapter for VA, and our nation’s veterans, has come to an end. But the volatile, damaging saga continues," said Paul Rieckhoff, founder and CEO of Iraq and Afghanistan Veterans of America. "It’s been an unprecedented time of chaos, political agendas and uncertainty. And millions of veterans and their families have paid the price."

The VA put out a statement on Wednesday with assurances the agency is focused on delivering Trump's promised improvements even with only temporary leadership in place. Trump appointed Robert Wilkie, an undersecretary at the Pentagon, as acting secretary until a permanent one is confirmed by the Senate.

"Under Acting Secretary Wilkie’s leadership, senior VA officials are now on the same page, speaking with one voice to Veterans, employees and outside stakeholders, such as Congress and veterans service organizations, and are focused on a number of key priorities in the short term," VA Press Secretary Curt Cashour said.

Those included working with Congress to get legislation passed that would allow veterans access to VA-sponsored care in the private sector, finalizing a contract to update the agency's medical record system and "working with the White House to get Admiral Ronny Jackson confirmed by the U.S. Senate."