Updated

The person responsible for ensuring that more than 12 million veterans get their benefits has resigned as undersecretary of the Veterans Benefits Administration.

Allison Hickey has served as an undersecretary at the Department of Veterans Affairs since June 2011. She was in charge as a backlog in disability claims pending for more than 125 days ballooned to about 611,000 in March 2013 and then fell by nearly 90 percent.

VA Secretary Robert A. McDonald says he regretfully accepted the resignation and credited Hickey for modernizing the disability claims process, moving it from a reliance on paper records to one in which records are stored on computer. McDonald said he appreciates all that Hickey has done to help transform the VA.

But Hickey was also coming under fire from veterans groups and lawmakers after a critical inspector general's report found that two other executives within the Veterans Benefits Administration received a total of about $400,000 in relocation expenses and retained their annual salaries despite a significant decrease in job responsibilities.

A House committee was scheduled to hold a hearing on that report next week. And 13 senators from both parties wrote McDonald last week demanding that he "hold accountable those who orchestrated, participated in, or benefited from the unethical practices outlined in this report, including but not limited to the Under Secretary for Benefits."

Rep. Jeff Miller, the chairman of the House Committee on Veterans' Affairs, was a longtime critic. He had called for her resignation going back to when Eric Shinseki ran the department; Hickey was one of the last top holdovers to remain from Shinseki's tenure as the VA secretary.

"Right now, VBA needs a leader who will put veterans, not VA bureaucrats first, while working to end the backlog without sacrificing quality, accuracy or service to veterans," Miller said. "Unfortunately, Hickey was not that type of leader."

Hickey served for more than 30 years in the Air force, Air National Guard and Air Force Reserve before retiring with the rank of brigadier general. "Her commitment to excellence and service to our country is unquestioned," McDonald said.