(CNN) -- Acting VA Secretary Sloan Gibson said he is frustrated and expects to have a plan in place to take "personnel actions" against employees responsible for manipulating patient wait lists at one VA medical center by the end of this week. He wouldn't identify the location of the center, but said it is not the Phoenix facility that has been at the epicenter of a wait-list scandal.
Gibson, the top official of the Department of Veterans Affairs, said the investigation process "takes a long time. And nobody is more frustrated about that than I am." He added that investigators at the Office of Inspector General are on the ground at more than 70 locations, and he needs to wait for each investigation to be complete before anyone can be fired.
The investigations came after months of CNN reports on deadly delays for veterans waiting for care at VA hospitals. Gibson was put in place temporarily after the ensuing firestorm forced the resignation of the former VA secretary, Eric Shinseki.
Gibson said he believes the behavior of VA employees has begun to change across the nation, but he wants to hold accountable the individuals responsible for fraudulent practices as soon as possible.
"Until people actually see those consequences I think they still don't trust it's a serious thing," Gibson said. "I want to set the tone."
Gibson spoke to CNN outside a hearing before the Senate Committee on Veterans Affairs on Wednesday; the acting secretary described an ongoing culture within the VA of faulty scheduling, long wait times, retaliation against whistle-blowers and lack of accountability for the leaders who have perpetuated these issues. In order to curb these failures, Gibson requested $17.6 billion over the next three years to hire 10,000 doctors and medical providers, pay for private health care appointments and increase the agency's infrastructure to meet veterans' needs.
"I believe in as little as two years, the conversation can change," Gibson said, indicating his confidence that his proposed solutions can transform the VA.
About $10 billion of the requested funds would cover the costs of additional VA staff and private care for veterans while about $6 billion would pay for new clinics and medical space, Gibson said.
Sen. Mike Johanns, R-Nebraska, challenged Gibson's request for additional funds, however, noting that Congress repeatedly approved more money at the request of former VA Secretary Eric Shinseki in years past, yet the backlog of appointments persisted.
Highlighting the severity of the issues, the committee's chairman, Sen. Bernie Sanders, I-Vermont, said more than 600,000 veterans are still waiting at least a month for appointments and about 8,000 are waiting at least four months.
"What are the legitimate needs? What are the real needs facing the 22 million veterans in this country?" Sanders asked. "We have an immediate crisis."
The Veterans Health Administration has reached out to more than 160,000 veterans to get them off wait lists and into medical centers, Gibson said, but he added that the VA needs to take drastic steps to restore trust with veterans and the American public at large.
Sen. Richard Blumenthal, D-Connecticut, said he has called for a criminal investigation by the Department of Justice into allegations that VA leaders intentionally manipulated patients' appointments.
"I do think that criminal responsibility has to be applied if there was ... destruction of documents, fraud in reporting," Blumenthal said.
Gibson told senators on Wednesday that he will not tolerate retaliation against whistle-blowers, but a panel of VA employees told the House Committee on Veterans Affairs last week that the threat of retaliation continues to silence individuals who have knowledge of wrongdoing.
After Shinseki's resignation, President Obama nominated the former chief executive of Procter & Gamble Co. and West Point graduate, Bob McDonald, to lead the VA.
McDonald will face a Senate confirmation hearing next week.