Members of the Senate Veterans' Affairs Committee have reportedly been informed of unverified allegations of misconduct against Rear Adm. Ronny Jackson, President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE's pick to the lead the Department of Veterans Affairs, posing a new roadblock for his nomination.

The Washington Post first reported Monday evening that the Senate panel is delaying a confirmation hearing for Jackson previously scheduled for Wednesday as members look into the new claims.

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Two sources told CNN that Republicans and Democrats on the committee have been informed of allegations of improper conduct at more than one stage in the career of Jackson, who currently serves as White House physician.

Staffers are reviewing allegations of a "hostile work environment," CBS News reported, including "excessive drinking on the job [and] improperly dispensing meds.”

"It'll sink his nomination" if the claims are true, one source told CBS, which reported that Veterans' Affairs Committee ranking Democrat Jon Tester Jonathan (Jon) TesterPence seeks to boost Daines in critical Montana Senate race This World Suicide Prevention Day, let's recommit to protecting the lives of our veterans Filibuster fight looms if Democrats retake Senate MORE (Mont.) had requested the hearing be delayed.

The White House did not respond to The Hill's request for comment.

“There’s a need for very exacting and close scrutiny and vetting,” Sen. Richard Blumenthal (D-Conn.) said, according to Politico. “And some questions that need to be answered. I’m not going to comment on any of the specifics, except to say we’re going to be doing very close and careful scrutiny.”

Tester told CNN that the allegations against Jackson would be considered troubling "only if true," adding that "we'll see" if Democrats could determine their veracity before Wednesday.

"All I can really tell you at this moment time is we are continuing the vetting process. We are working very hard at it. It's all hands on deck," Tester said.

Jackson was tapped by Trump to replace former Veterans Affairs Secretary David Shulkin David Jonathon ShulkinVA inspector general says former top official steered M contract to friend Schumer demands answers in use of unproven coronavirus drug on veterans Former Trump VA secretary says staffer found plans to replace him in department copier MORE last month.

....In the interim, Hon. Robert Wilkie of DOD will serve as Acting Secretary. I am thankful for Dr. David Shulkin’s service to our country and to our GREAT VETERANS! — Donald J. Trump (@realDonaldTrump) March 28, 2018

Shulkin, Trump's only Cabinet secretary to have served in the Obama administration, had faced backlash for his use of taxpayer dollars on travel.

Shulkin was confirmed unanimously and appeared in the White House briefing room during the first year of the Trump administration to promote accomplishments.

While Jackson is an active-duty Navy admiral who has been the physician to the president since 2013, various lawmakers have raised concerns over his fitness to run the VA, which is the second-largest government bureaucracy.

He gained national attention earlier this year when he revealed the results of Trump's physical examination, telling reporters at the White House that the president has "good genes."

Updated at 10:26 p.m.