President Trump on Saturday called for Montana Sen. Jon Tester’s resignation, after a White House’s report disputing his allegations against the president's pick for the next secretary of Veterans Affairs, Ronny Jackson.

“Allegations made by Senator Jon Tester against Admiral/Doctor Ron Jackson are proving false,” Trump said over two tweets. “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.”

He continued: “The 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!”

Jackson, the White House doctor and a Navy Admiral, withdrew his nomination to lead the Department of Veterans Affairs on Thursday amid allegations collected by Tester’s office about his prescription-drug practices and use of alcohol. Among the allegations, Jackson was accused of getting drunk and wrecking a government vehicle after a Secret Service going-away party.

Tester, the top Democrat on the Republican-controlled Senate Veteran Affairs Committee, is seeking a third Senate term this year in a state Trump won in 2016 with 56 percent of the vote.

In response to Trump, Tester issued the following statement on Saturday:

“It's my duty to make sure Montana veterans get what they need and have earned, and I'll never stop fighting for them as their senator," he said.

Trump tweeted again on the matter later saying, "Secret Service has just informed me that Senator Jon Tester's statements on Admiral Jackson are not true."

"There were no such findings," he continued. "A horrible thing that we in D.C. must live with, just like phony Russian Collusion. Tester should lose race in Montana. Very dishonest and sick."

On Friday, the White House pushed back again the allegations, saying records, including police reports, show Jackson was in three minor vehicle incidents in government vehicles during the last five years, but none involved the use of alcohol and he was not found to be at fault.

In one case, a side-view mirror was clipped by a passing truck, while in another incident an enraged driver in Montgomery County, Maryland, allegedly punched out Jackson’s window during a morning drive to Camp David.

In addition, the White House medical unit Jackson ran found that he successfully passed regular controlled substance audits, according to the records for the last three years. The reviews did recommend improvements to the medical unit’s handling of controlled substances but did not find misconduct.

The Associated Press reviewed the documents Friday. They were the result of an internal White House review of allegations raised against Jackson during his brief confirmation process. The White House said the records, covering recent years, disprove the allegations.

Tester’s office has not specified the time frame during which the alleged misconduct occurred. The senator’s spokeswoman Marnee Banks said the office would not comment until it knew more about the White House records.

Separately, the Secret Service said it has no evidence to support an allegation that its personnel intervened to prevent Jackson from disturbing former President Barack Obama during a foreign trip in 2015.

In a statement dated Thursday, the Secret Service said it had conducted a “thorough review” of internal documents related to Obama’s foreign trips in 2015 and interviewed people who were present. The agency said it has found “no information that would indicate the allegation is accurate” and no record of any incident involving Jackson.

CNN had reported allegations that Jackson drunkenly banged on the hotel room door of a female employee and that Secret Service personnel intervened out of concern that he would wake Obama.

Jackson has denied the accusations, calling them “baseless and anonymous attacks” on his character and integrity that are “completely false and fabricated.”

Asked about the situation at a joint press conference with German Chancellor Angela Merkel, Trump called the Jackson situation “an absolute disgrace.”

“These were false accusations about a great man; about a man who has a son who’s a top student at Annapolis; about a man that’s given his life to this country, and to the military — a brave man. He would have been a great leader,” Trump complained, noting that he, Obama and former President George W. Bush had all praised the doctor’s conduct in the past.

Trump said he’d called Jackson earlier Friday and told him that he was “an American hero” because he’d “exposed the system for some horrible things.”

The Democratic staff on the committee considering Jackson’s nomination also claimed Jackson had doled out such a large supply of a prescription opioid that staffers panicked because they thought the drugs were missing.

They said their allegations were based on conversations with 23 of Jackson’s current and former colleagues at the White House Medical Unit.

The Associated Press contributed to this report.