Breaking News Emails

Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

A top official in charge of veterans' health care stepped down Friday, the first head to roll in a growing scandal over delayed and substandard care at U.S. Department of Veterans Affairs hospitals.

Undersecretary Robert Petzel submitted his resignation a day after he and Veterans Affairs Secretary Eric Shinseki were grilled by federal lawmakers over allegations of long wait times, substandard care, and falsified records at VA medical centers around the country.

Veterans Affairs Undersecretary Robert Petzel, MD testifies on Capitol Hill in Washington, Thursday, May 15, 2014, before the Senate Veterans Affairs Committee hearing to examine the state of Veterans Affairs health care.Cliff Owen / AP

In one case, a whistleblower has alleged that up to 40 veterans died while awaiting appointments in a VA facility in Phoenix.

Petzel, a career VA doctor who had been undersecretary since 2010, had previously planned to retire later this year -- President Obama had already announced plans to nominate his replacement. On Thursday, the same day Petzel and Shinseki appeared before the Senate Committee on Veterans' Affairs, USA Today published an op-ed in which Petzel said he was “personally saddened” by any case of a veteran receiving poor care. He vowed "prompt and appropriate action" if the allegations of misconduct turned out to be substantiated by the agency’s inspector general.

But Shinseki had already lost confidence in Petzel, and on Friday asked him to resign, a source told NBC News.

Shinseki followed the resignation with a statement in which he said the VA "must do more to improve timely access" to veterans' heath care.

"I am committed to strengthening veterans' trust and confidence in their VA healthcare system," Shinseki said.

Obama said in a statement that he supported Shinseki's decision, and that he was committed to investigating the misconduct allegations. The president also thanked Petzel for his "many years of service to veterans."

Rep. Jeff Miller, a Republican who chairs the House Committee on Veterans' Affairs, said Petzel's resignation did nothing to hold anyone at the VA accountable, since he was going to leave anyway.

The VA "has resorted to what it does best: splitting semantic hairs to create the illusion of accountability and progress," Miller said.

Sen. Jerry Moran, a Republican who sits on the Senate Committee on Veterans' Affairs, said Petzel "should not shoulder the blame for VA's failures." Instead, "action should be taken immediately to change the bureaucratic culture of mediocrity at the VA and ensure the highest quality and most timely care for our nation's heroes."

A Petzel deputy, Robert Jesse, will serve temporarily as acting undersecretary of health until a permanent replacement is confirmed by the Senate.

—with Jim Miklaszewski