Senators have postponed their confirmation hearings for Rear Adm. Ronny L. Jackson, President Donald Trump s nominee to head the Department of Veterans Affairs, after concerns arose over the White House doctors qualifications and allegations regarding his conduct.

Sens. Johnny Isakson (R-Ga.) and Jon Tester (D-Mont.) announced the delay Tuesday morning, after The Washington Post and other outlets reported Monday that the postponement was forthcoming. They didnt specify when the hearing will take place.

Sources told CBS News and The New York Times that Tester and his staff are looking into allegations that Jackson created a hostile work environment, including excessive drinking on the job and improperly dispensing meds.

A 2012 report by the Navys medical inspector general detailed a rivalry between Jackson and Dr. Jeffrey Kuhlman in a power struggle over the White House medical unit, according to an Associated Press report Tuesday . The report suggested replacing either doctor, or both, to resolve the low morale and lack of trust in the leadership among the medical unit staff.

Staff members at the time described the situation as being caught between parents going through a bitter divorce, according to the AP.

Trump nominated Jackson to become the next secretary of veterans affairs in March after the White House announced that David Shulkin would be leaving the post . Critics began to worry that Jacksons career in the military lacked the managerial experience necessary to tackle the monolithic department.

It was these concerns by both top Republicans and Democrats that have delayed the confirmation process, the Post reported, just two days before hearings were scheduled to begin .

There are reasons, as there are with every presidential appointee, for very close scrutiny and vetting, Sen. Richard Blumenthal (D-Conn.) told CNN Monday. We need to know if allegations raised by others may have some factual basis. Thats the process of vetting that has to occur.

Asked about the allegations on Tuesday, Trump praised Jackson as one of the finest people that I have met and a great doctor, but hinted Jackson possibly should withdraw his name from consideration .

He has to listen to the abuse, he said at a joint news conference with French President Emmanuel Macron, referring to the allegations. I wouldnt do it. What does he need it for? To be abused by a bunch of politicians.

Jackson has been the White House physician since 2013, serving both Trump and Barack Obama . Though the rear admiral came under fire after briefing the media on Trumps health in January , former Obama advisers defended Jackson as a phenomenal doctor .

This story has been updated with senators officially delaying the hearings, more information about the allegations against Jackson and comments from Trump.