WASHINGTON - US President Donald Trump’s doctor Ronny Jackson withdrew his nomination to head the Department of Veterans Affairs on Thursday following allegations he improperly handed out drugs and was drunk at work.

The withdrawal - just the latest staffing upset in an administration rocked by a series of firings and resignations - came as the head of the Environmental Protection Agency was grilled by Congress over mounting ethical scandals.

“I am regretfully withdrawing my nomination to be Secretary for the Department of Veterans Affairs,” Jackson said in a statement. Jackson insisted that the allegations against him were false, but said he was withdrawing anyway due to the distraction they were causing. “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,” Jackson said.

His withdrawal came just a day after he indicated that he would fight on, telling reporters his surprise nomination was “still moving ahead as planned.” Trump told Fox News he had seen the writing on the wall, but defended Jackson, saying he would have done a “great job.” “He’s a great man, and he got treated very, very unfairly,” Trump later said.

The president’s daughter Ivanka also came to Jackson’s defense and indicated that he would stay on in his current job, writing on Twitter: “We... look forward to continuing to see his warm smile each day at the White House!” Jackson’s withdrawal was not the only troubling news for Trump’s administration on Thursday: lawmakers grilled the embattled head of the EPA, Scott Pruitt - one of several cabinet members to be dogged by allegations of improper expenditures. Pruitt has notably been under fire for lavish spending on first-class travel with a large security detail, for a discount he received on a condominium linked to a lobbying firm, and for allegedly sharply boosting salaries of close aides at the agency.

House Democrat Frank Pallone told Pruitt that in any other administration, “you would be long gone by now,” saying he had brought “secrecy, conflicts of interest, and scandal to the EPA.”

Pruitt hit back, saying he had “nothing to hide” and that the criticism of him and the EPA was aimed at derailing Trump’s agenda.

“I’m simply not going to let that happen,” he said.

An ethics issue helped bring down David Shulkin, the previous head of the 380,000-plus employee Department of Veterans Affairs (VA), who was sacked in late March after he was accused of spending $122,000 on a nine-day trip to Europe with his wife, which included sightseeing at castles and taking in professional tennis matches.

The agency is notoriously dysfunctional, and a lack of funding has weakened the hospital network specifically dedicated to the health of veterans - a key constituency for Trump.

- ‘Candy man’ -

The system has come under criticism for falling short, particularly in terms of psychiatric care for those suffering from post-traumatic stress disorder.

Trump surprised even his closest aides a month ago with an evening tweet announcing Jackson was his pick to run the VA.

The Navy rear admiral was the physician to presidents Trump, Barack Obama and George W. Bush and was well regarded by many current and former White House staff.

But he was widely seen as underqualified to head the VA and already faced a tough battle for congressional confirmation.

Jackson’s stock with Trump appeared to have risen after he pronounced in January that the 71-year-old president was in “excellent” health.

But following the announcement of his nomination, a wave of allegations surfaced over his behavior, including that he doled out drugs to staffers like the “candy man” and crashed a government vehicle.

Senate Democrats released a litany of allegations on Wednesday, citing “conversations with 23 colleagues and former colleagues.”

These included that he handed out sleeping tablets on Air Force One, opioids to at least one White House staffer and prescribed drugs for himself.

“On at least one occasion, Dr Jackson could not be reached when needed because he was passed out drunk in his hotel room,” according to a document released by Democratic Senator Jon Tester.