Department of Veterans Affairs Secretary Eric Shinseki adjusts his glasses as he takes his seat to testify before a Senate Veterans Affairs Committee hearing on VA health care  on Capitol Hill on May 15. (Jonathan Ernst/Reuters)

President Obama has dispatched one of his closest advisers to oversee a review of the Department of Veterans Affairs, which is dealing with fallout over clinics that allegedly covered up delays in treatment for veterans.

Rob Nabors, a White House deputy chief of staff, will assist the VA on a temporary basis, the White House said Wednesday. He will work with the VA on an ongoing assessment of its practices and help develop recommendations on how veterans' hospitals can increase access to timely care.

The announcement comes as pressure has mounted on Veterans Affairs Secretary Eric Shinseki after allegations that a hospital in Phoenix created a secret list to hide that veterans had to wait months to access care. According to a CNN report, at least 40 patients died while waiting to see a doctor. According to USA Today, a clinic in Fort Collins, Colo., faked records to make it appear as though doctors were seeing a certain number of patients each day. The allegations come on top of a backlog of disability claims at the VA.

Shinseki is testifying Thursday about the state of the VA before the Senate Veterans Affairs Committee. The American Legion called for Shinseki's ouster this month.

Obama directed Shinseki to review policies and procedures surrounding patient scheduling and compliance with patient safety rules when the allegations about the Phoenix center surfaced. Shinseki also asked the VA's independent inspector general to investigate the allegations, placed officials at the Phoenix center on leave and asked for additional staff to review how VA patients access care. Shinseki asked the Veterans Health Administration to review how veterans access VA facilities to "ensure full compliance with scheduling policy," he said in a statement.

White House Chief of Staff Denis McDonough asked Nabors to temporarily assist at the VA.

"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. That’s why I asked Secretary Shinseki to review practices to ensure better access to care," Obama said in a statement. "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.”

RNC Chairman Reince Priebus is calling for an independent investigation into problems at the VA.

Our veterans are our heroes and they deserve better than a White House insider-led investigation," he said in a statement. "They deserve an independent investigation. Yet again the White House is trying to pass off a scandal as an isolated incident when in fact it continues to grow every day. There are reports that at least 40 veterans have died waiting for care. It’s time for an independent investigation.”

Nabors, 43, is the son of an Army veteran and has worked on domestic and economic policies in the White House, and was previously director of the White House Office of Legislative Affairs. Among the other issues he has tackled at the White House is reducing the number of veterans' disability claims at the VA over the past year.

“Our Nation’s Veterans deserve to have full faith in their health care.  I welcome Rob’s 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," Shinseki said in a statement.

"We will continue to improve the quality and safety of VA health care – America’s Veterans deserve nothing less,” he said.

This post has been updated to add Priebus's statement and to clarify that Nabors worked on reducing disability claims over the past year.