The Department of Veterans Affairs top health official was asked to resign Friday by VA Secretary Eric Shinseki in the wake of the growing scandal over whether wait times in care at a Phoenix VA Medical Center may have resulted in patient deaths.

The VA announced last September that Dr. Robert Petzel, the VA's under secretary for health, would retire after his successor was confirmed by the Senate.

However, a VA official told ABC News that on Friday Shinseki asked Petzel resign ahead of his planned retirement. Petzel had sat next to Shinseki at Thursday's hearing by the Senate Veterans Affairs Committee into care at the Phoenix facility and other VA facilities across the country.

According to the VA official "the secretary requested and accepted his resignation today. Previously in September, 2013 VA had announced Dr. Petzel's retirement and that he would continue to serve in his position until the Senate confirmed a new Under Secretary for Health, and today the Secretary requested and received Dr. Petzel's resignation."

The official would not point to a specific reason as to why Shinseki had asked for Petzel's resignation but said that on Thursday "the secretary listened to hours of testimony, as well as members of the committee and takes their concerns seriously. While VHA (Veterans Health Administration) has made efforts to address healthcare appointment scheduling and wait times for health care, further improvement is needed. "

The official said Shinseki "will continue to take decisive action to improve timely access to quality VA health care."

In a statement announcing he had accepted Petzel's resignation, Shinseki thanked him for his 40 years of service to veterans but said, "As we know from the Veteran community, most veterans are satisfied with the quality of their VA health care, but we must do more to improve timely access to that care." He added, "I am committed to strengthening Veterans' trust and confidence in their VA healthcare system."

A White House statement said: "The President supports Secretary Shinseki's decision. As the President has said, America has a sacred trust with the men and women who have served our country in uniform and he is committed to doing all we can to ensure our veterans have access to timely, quality health care."

Petzel's successor, Dr. Jeffrey A. Murawsky, was nominated on May 1, 2014 and his nomination has not been taken up by the Senate. Dr. Robert L. Jesse, currently the VA's principal deputy under secretary for health, will serve as Acting Under Secretary until Murawsky is confirmed.

The previously announced retirement in September, 2013, led some of Shinseki's critics on Capitol Hill to claim that Petzel's resignation was actually his planned retirement.

Rep. Jeff Miller, chairman of the House Veterans Affairs Committee, said he was "disappointed" by the announcement because it created "the illusion of accountability and progress."

He added, "today's announcement from VA regarding Undersecretary for Health Robert Petzel's 'resignation' is the pinnacle of disingenuous political doublespeak," and that "characterizing this as a 'resignation' just doesn't pass the smell test."

At Thursday's hearing Shinseki said he was "mad as hell" about the reports that treatment delays may have caused the deaths of some patients though he would not resign as members of Congress and the American Legion have demanded. Shinseki told the committee "I came here to make things better for veterans…this is not a job. I'm here to accomplish a mission that I think they critically deserve and need. "

The VA Inspector General is currently investigating allegations made by a whistleblower that staff at the Phoenix facility doctored wait time documents for patients seeking care to make it seem they were complying with the VA's standard that patients receive care within two to four weeks. An ongoing IG investigation is looking into whether wait time delays resulted in the deaths of as many as 40 veterans as the whistleblower alleges.

While a final report is not anticipated until later this summer, on Thursday acting VA IG Richard Griffin told the Senate Veterans Affairs Committee that an review of an initial list of 17 people who experienced delays in care at the Phoenix facility had not conclusively shown that the delays had contributed to their deaths.

"It's one thing to be on a waiting list, and it's another thing to conclude that as a result of being on the waiting list that's the cause of death, depending on what your illness might have been at the beginning," Griffin told the Committee.