Nominee Ronny Jackson withdrew from consideration this week, although has denied allegations against him
Donald Trump has called for a Democratic senator to resign amid an ongoing row over allegations about Ronny Jackson, the White House doctor who this week withdrew as a nominee for Trump's cabinet.
Dr Jackson - who has served as physician to the president since 2013 - had been nominated as secretary of veteran affairs.
He withdrew from consideration earlier this week in the wake of a series of claims about his conduct on the job.
According to New York Times, Democratic Senator Jon Tester released a list of accusations against Dr Jackson - which the paper describes as allegations of "loose distribution of prescription drugs, a hostile work environment and drunkenness".
Dr Jackson has described the allegations as "completely false and fabricated".
In a statement he said: "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.
"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."
US media reported yesterday that the US Secret Service has disputed some of the allegations against Dr Jackson - saying it had no record of an alleged incident during an overseas trip in which they were reportedly forced to intervene to prevent Dr Jackson from disturbing Barack Obama.
In a pair of tweets this morning, meanwhile, President Trump wrote: "Allegations made by Senator Jon Tester against Admiral/Doctor Ron Jackson are proving false.
"The Secret Service is unable to confirm (in fact they deny) any of the phony Democrat charges which have absolutely devastated the wonderful Jackson family. Tester should resign."
....great people of Montana will not stand for this kind of slander when talking of a great human being. Admiral Jackson is the kind of man that those in Montana would most respect and admire, and now, for no reason whatsoever, his reputation has been shattered. Not fair, Tester!— Donald J. Trump (@realDonaldTrump) April 28, 2018
Senator Tester represents Montana, and faces an election race this year in a state that saw a resounding victory for Donald Trump over Clinton.
Following Dr Jackson's withdrawal, Senator Tester said he wanted to work with Republicans to vet and confirm a veteran affairs secretary.