WASHINGTON - White House physician Ronny Jackson announced Thursday that he had withdrawn from President Donald Trump's nomination to be the next Veterans Affairs Secretary, in the wake of a series of allegations that he had fostered a hostile work environment and behaved improperly while serving as the top doctor in the White House.

"Unfortunately, because of how Washington works, these false allegations have become a distraction for this President and the important issue we must be addressing ...," Jackson, a rear admiral, said in a statement released by the White House on Thursday morning.

"While I will forever be grateful for the trust and confidence President Trump has placed in me by giving me this opportunity, I am regretfully withdrawing my nomination to be Secretary for the Department of Veterans Affairs," he said.

Trump told Fox News on Thursday morning that "it's a disgrace" the way his nominees have been treated, including Jackson.

On Tuesday, US Senate Committee on Veterans' Affairs said it has delayed indefinitely a confirmation hearing for Jackson's nomination since lawmakers need more time to vet the White House doctor's controversial record.

Senator Jon Tester, a Democrat on the committee, then detailed the allegations including creating a hostile workplace, drinking while on duty and improperly prescribing the opiate painkiller Percocet to White House staff during overseas trips in an interview with the National Public Radio (NPR).

The allegations came from more than 20 military employees who approached senators ahead of Jackson's confirmation hearing, according to NPR, the biggest radio network in the country.

Trump announced Jackson's nomination last month after the departure of Veterans Affairs Secretary David Shulkin, who had been confirmed with unanimous bipartisan support in the Senate.

"Adm. Jackson is highly trained and qualified and as a service member himself, he has seen firsthand the tremendous sacrifice our veterans make and has a deep appreciation for the debt our great country owes them," Trump said when announcing his pick.

Jackson has served as a White House physician since 2006 and was selected by then President Barack Obama to be the chief doctor in the White House medical unit in 2013. Trump kept him on the job since taking office in January 2017.

The US Department of Veterans Affairs has more than 300,000 employees and 1,200 medical facilities across the country.