(Adds House passage of VA disciplinary legislation)
By Steve Holland and Roberta Rampton
WASHINGTON, May 21 (Reuters) - U.S. President Barack Obama vowed on Wednesday to get to the bottom of allegations that veterans suffered long delays in getting healthcare and made clear Veterans Affairs Secretary Eric Shinseki's job may be on the line, as he scrambled to contain a spreading controversy.
"If these allegations prove to be true, it is dishonorable, it is disgraceful, and I will not tolerate it, period," an angry Obama said.
The president appeared in the White House press briefing room moments after meeting Shinseki and Rob Nabors, the top Obama aide who is leading a review into allegations that long wait times for veterans seeking medical treatment could have led to some deaths.
He said he expects to get the preliminary results of a review about the scope of the problem at the Veterans Administration next week, and that anyone found to have manipulated or falsified records at the VA must be held accountable.
"When I hear allegations of misconduct, any misconduct, whether it's allegations of VA staff covering up long wait times or cooking the books, I will not stand for it, not as commander in chief, but also not as an American," Obama said.
Obama sidestepped a question as to whether Shinseki had tendered his resignation, but hinted that the retired four-star army general may not want to stay on if it turns out the allegations are as sweeping as suggested.
"If he thinks he's let our veterans down, then I'm sure that he is not going to be interested in continuing to serve," Obama said. "At this stage, Ric is committed to solving the problem and working with us to do it."
Until now, the White House has insisted Shinseki enjoyed Obama's confidence and officials have drawn parallels between him and Kathleen Sebelius, who stayed on as secretary of health and human services for months trying to clean up problems with the rollout of Obama's signature healthcare law.
The veterans' controversy has exploded in the midst of an election year in which Republicans seem poised to make gains in the U.S. Congress against Obama's Democrats.
Republicans were quick to pounce on Obama's first comments about the controversy since late last month.
"We need answers, leadership and accountability, none of which we've seen from the Obama administration to date," said Republican Senator John McCain.
The Republican-controlled House of Representatives overwhelmingly passed legislation that would give Shinseki greater authority to fire or demote VA employees for non-performance.
"If you don't do your job, you get fired," said Representative Jeff Miller, the Republican chairman of the House Veterans Affairs Committee.
Instead, he said Phoenix VA medical center director Sharon Helman, who was put on administrative leave pending the outcome of an investigation into allegations that long wait times for care at the local VA hospital and clinics were covered up, received an $8,500 bonus in April.
Shinseki on Wednesday rescinded that bonus, which was granted in error, the VA said.
The VA reports are the latest allegations of bureaucratic mismanagement to hit the Obama administration after the botched rollout of the national healthcare website and the Internal Revenue Service's targeting of conservative groups for special scrutiny.
The flap is particularly biting for Obama because he and his wife, Michelle, have put much time into caring for veterans who have returned from combat in Iraq and Afghanistan, many of them with disabling injuries.
Nabors, a deputy White House chief of staff, will travel to Phoenix on Wednesday to look into allegations of long wait times for veterans seeking healthcare.
Two top VA officials have resigned in recent weeks, and allegations involving delays have been made at other veterans' medical facilities. Officials have said 26 such facilities were now under investigation.
The Veteran Affairs department oversees some 1,700 hospitals, clinics, nursing homes and other facilities, making it the nation's largest healthcare organization. (Additional reporting by Mark Felsenthal and David Lawder; Editing by Jim Loney and Andre Grenon)