Veterans Affairs Secretary Bob McDonald on Tuesday expressed regret over comments he made a day earlier in which he downplayed the time it takes for military veterans to receive treatment by comparing the wait times at VA facilities to lines at Disneyland.

"It was never my intention to suggest that I don't take our mission of serving veterans very seriously," McDonald said in a statement. "If my comments Monday led any veterans to believe that I, or the dedicated workforce I am privileged to lead, don't take that noble mission seriously, I deeply regret that. Nothing could be further from the truth."

McDonald said that "improving access to care is my number one priority" and that VA employees have worked "tirelessly" over the last two years to improve the timeliness of treatment and benefits.

On Monday, he came under fire for remarks he made at a breakfast with reporters.

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"The days to an appointment is really not what we should be measuring. What we should be measuring is the veteran's satisfaction," McDonald told reporters at a Christian Science Monitor breakfast in Washington, according to The Hill newspaper. "When you go to Disney, do they measure the number of hours you wait in line?" he asked. "What's important is what's your satisfaction with the experience."

Republicans blasted McDonald for the comment. Sen. Roy Blunt, R-Missouri, even called on McDonald to resign for his "preposterous statement."

"I call on him to resign because it's clear he cannot prioritize getting our veterans the health care they deserve and have earned in a timely manner. Dismissing wait times when veterans can often wait months for an appointment is negligent and a clear sign that new leadership is needed at the VA," Blunt said in a statement Tuesday.

Speaker Paul Ryan, R-Wisconsin, called the comment "disgusting" at a press conference on Tuesday morning, but he stopped short of calling for McDonald's resignation.

"I don't know if he should resign. He should clarify his comments. He should show some empathy for the veterans he is supposed to serve," he said.

McDonald, the former CEO of Procter & Gamble, has served as the head of the VA since 2014. He took over after his predecessor, Secretary Eric Shinseki, resigned that year over the scandal that plagued the department with wait times that reportedly left as many as 40 people dead at a Phoenix VA hospital.

CBS News' Walt Cronkite contributed to this report.