Veterans Affairs secretary Eric Shinseki was brought before a Senate committee on Thursday, where he answered bipartisan criticism and vowed not to resign. He said that he is “mad as hell” over the VA’s health care system delays.

The VA has been under a microscope in recent weeks, as the scandal over wait times at VA hospitals around the country have been linked to the deaths of veterans. The Phoenix VA hospital has been at the center, as the delays there may have lead to at least 40 veterans’ deaths.

Congress subpoenaed Shinseki last month, as calls for his resignation grew louder. He refused to resign and did so again today.

“Do you believe you are ultimately responsible for all of this?” Sen. Dean Heller (R-Nev.) asked Shinseki during the hearing before the Senate committee on Veterans’ Affairs, reports NBC News.

After Shinseki said he thought he was, Heller asked, “Can you explain to me why, after knowing all of this information, you should not resign?”

“I came here to make things better for veterans. That was my appointment by the president,” Shinseki explained. “I intend to continue this mission until I have satisfied either that goal, or I am told by the commander-in-chief that my time has been served.”

Earlier at the hearing, the retired general expressed his anger over the situation. “Any allegation, any adverse incident like this makes me mad as hell,” Shinseki said, notes CNN. He added that “we will act” on any allegation. That was clearly not enough for the senators, who wanted to see action as soon as possible.

The senators noted how the issues over fixed scheduling and long wait times for health care for veterans has been well known for over a year and that the VA should have known. “VA senior leadership, including the secretary, should have been aware that the VA is facing a national scheduling crisis,” Sen. Richard Burr (R-NC) said at the start of the hearing.

Sen. Richard Blumenthal (D-Conn.) said that law enforcement should be brought in because there is evidence - not just allegations - that books had been falsified to say that veterans had been served, even if they weren’t.

Sen. John McCain (R-Ariz.) added that the issues have created a “crisis of confidence” and that “We should all be ashamed,” reports Fox News.

“Manipulation of data of the truth is serious,” Shinseki told Sen. Mark Begich (D-Alaska), who insisted that Shinseki begin firing anyone who faked documents. “There is a process here, Senator. Let me not get out ahead of it.”

Although the White House has stood behind Shinseki, the Obama Administration did appoint White House Deputy Chief of Staff Rob Nabors to assist in the investigation into the issues.

“While we get to the bottom of what happened in Phoenix, it's clear the VA needs to do more to ensure quality care for our veterans,” President Obama said when he appointed Nabors to the job.