(AP) -- With outrage mounting over veterans' health care, President Barack Obama declared Wednesday that allegations of misconduct at VA hospitals will not be tolerated, and he left open the possibility that Secretary Eric Shinseki, a disabled war veteran, could be held to account.

"I will not stand for it -- not as commander in chief but also not as an American," Obama said following an Oval Office meeting with the embattled Shinseki.

Congress moved to keep up the pressure on the administration, with the House easily approving a measure Wednesday evening that would give the VA secretary more authority to fire or demote the 450 senior career employees who serve as hospital directors or executives in the agency's 21 regions. The vote was 390 to 33.

Rep. Jeff Miller, R-Fla., chairman of the House Veterans Affairs Committee, sponsored the measure, saying VA officials who have presided over mismanagement or negligence are more likely to receive bonuses or glowing performance reviews than any sort of punishment. He declared that a "widespread and systemic lack of accountability is exacerbating" the department's problems.

The White House said it supported the goal of seeking greater accountability at the VA but had unspecified concerns about the legislation.

The growing furor surrounding the Department of Veterans Affairs centers on allegations of treatment delays and preventable deaths at VA hospitals. The department's inspector general's office says 26 facilities are being investigated nationwide, including a Phoenix hospital facing allegations that 40 people died while waiting for treatment and staff kept a secret list of patients in order to hide delays in care.

The allegations have raised fresh concerns about the Obama administration's management of a department that has been struggling to keep up with the influx of new veterans returning home from the wars in Iraq and Afghanistan. Obama's comments Wednesday -- his first on the matter in more than three weeks -- signaled a greater urgency by the White House to keep the matter from spiraling into a deeper political problem in a midterm election year.