President Obama is sending over one of his most trusted advisers to help fix an array of problems at the beleaguered Veterans Affairs Department.

Rob Nabors, White House deputy chief of staff, will be temporarily dispatched to the VA to oversee an internal review focused on policies for patient safety rules and the scheduling of patient appointments, officials said Wednesday.

The move comes ahead of VA Secretary Eric Shinseki's scheduled testimony Thursday morning before the Senate Veterans Affairs Committee and amid a torrent of calls for his resignation among veteran groups and on Capitol Hill.

The VA has suffered from a steady stream of allegations in recent weeks and months. In addition to trying to reduce a stubbornly unwieldy claims backlog, the VA faces charges that it has used accounting tricks to reduce claim numbers, has gamed treatment delays and allowed 40 preventable deaths at a Phoenix veterans hospital.

The Washington Examiner has broken several of the stories. Earlier this month, the Examiner revealed that more than 1.5 million backlogged orders for medical tests were mass canceled by VA officials without any assurance the veterans got the tests or other procedures that had been ordered.

That practice was initially found by the Examiner in Los Angeles and Dallas, where tens of thousands of medical orders were purged by the agency to reduce appointment backlogs.

The Examiner on Monday reported that veterans in the VA's health system in southeast Texas faced delays or denials in getting routine colonoscopies and other potentially life-saving tests because of cost-cutting policies there.

Before dispatching Nabors to the VA, Obama had only spoken about the brewing scandal once in response to a reporter's question more than two weeks ago while traveling in Manila, Philippines.

At the time, he said he had ordered Shinseki to investigate the allegations of the up to 40 Arizona veterans deaths in Phoenix and said he takes the allegations “very seriously.” He also noted that the VA inspector general is also investigating.

The president also made the point that he's increased the VA's budget more than any other agency in the government.

Since that time, however, Obama has remained silent on the issue, even after the American Legion, one of the nation's oldest and most influential veterans organizations, called for Shinseki to resign. It was the first time the Legion has called on a public official to step down since 1978.

White House press secretary Jay Carney this week has repeatedly said Obama remains confident in Shinseki's ability to lead the agency.

On Wednesday, Obama released an official statement.

“America has a sacred trust with the men and women who serve our country in uniform — one that continues when they come home — and we must do everything to keep that trust," he said. "That’s why I asked Secretary Shinseki to review practices to ensure better access to care."

"While we get to the bottom of what happened in Phoenix, it’s clear the VA needs to do more to ensure quality care for our veterans. I’m grateful that Rob, one of my most trusted advisors, has agreed to work with Secretary Shinseki to help the team at this important moment.”

Earlier this week, reporters called on the White House to take similar action that it did when technical glitches were sinking and threatening the Obamacare rollout and assign a top White House aide to shepherd attempts to fix the problem. The White House last fall dispatched Obama aide Jeffrey Zients to take over management of the website improvements. Health and Human Services Secretary Kathleen Sebelius later resigned her post.

Nabors, the son of an Army veteran, is one of Obama's closest advisers. He also is one of the few Obama administration aides who has served in a Hill liaison position who is well-liked and respected among Republicans on Capitol Hill for his outreach efforts. Nabors was appointed deputy chief of staff after Obama was re-elected.

Nabors has worked on a number of domestic and economic policies during his White House tenure, including reducing the backlog of veterans' disability claims at the VA over the last year, according to a White House official. In addition to his Hill liaison duties, Nabors has served has deputy director of the Office of Management and Budget and previously served as the staff director of the House Appropriations Committee when Democrats controlled the majority.

The White House says Shinseki requested additional staff to assist in its review of patient access to care and White House Chief of Staff Denis McDonough agreed to send over Nabors.

Shinseki said he welcomes Nabors' "perspective in helping us to ensure Veterans have access to timely quality health care."

"If allegations about manipulation of appointment scheduling are true, they are completely unacceptable – to veterans, to me, and to our dedicated VA employees," he said. "... We will continue to improve the quality and safety of VA health care — America’s Veterans deserve nothing less.”

Veterans groups also welcomed the move.

"We are glad the president took this first step to ensure the White House is involved in solving this crisis at the VA," said Tom Tarantino, the chief policy officer of Iraq and Afghanistan Veterans of America. "We need bold reform to establish a culture of accountability throughout the VA system and hope that Mr. Nabors' presence will help ensure that this type of failure never happens again."

This story is based in part on wire reports. Story was first published at 9:24 a.m. and has been updated.