Senator John McCain
Senator John McCain Reuters

Senator John McCain (R-AZ) came out on Sunday saying he will back Republican nominee Donald Trump, even as he criticized other leading Republican figures who announced they are unwilling to support the real estate mogul over his controversial statements.

McCain's support comes despite his saying in March that he has serious concerns about Trump, backing former Republican nominee Mitt Romney in his criticism.

The 79-year-old former Republican presidential nominee from 2008 told CNN Sunday that party leaders who don't want to back Trump are "out of step" with the voting public that has made its preference known, and he asserted Trump is a strong and "capable" leader.

At the same time, McCain called on Trump to "retract" his prisoners of war criticism, in a sensitive topic given that McCain was himself the target of Trump's criticism, and likewise called for him to stop his personal attacks.

"Frankly, I have never seen the personalization of a campaign like this one, where people's integrity and character are questioned. It bothers me a lot. Because you can almost violently disagree with an issue, but to attack their character and their integrity - then those wounds take a long time to heal," said the senior senator.

He called on Trump to unite the Republican party, and voiced his criticism when asked about the refusal of House Speaker Paul Ryan and Senator Lindsey Graham (R-SC) to back Trump.

"You have to draw the conclusion that there is some distance, if not a disconnect, between party leaders and members of Congress and the many voters who have selected Donald Trump to be the nominee of the party," McCain said.

"You have to listen to people that have chosen the nominee of our Republican Party. I think it would be foolish to ignore them."

At the same time, McCain said "a lot of things would have to happen" before he would appear on the campaign stage with Trump.

"I think it's important for Donald Trump to express his appreciation for veterans, not John McCain, but veterans who were incarcerated as prisoners of war," he said.

The comment by McCain, who was captured and tortured by the North Vietnamese in the Vietnam War, refers to Trump's shocking attack on the senator last year, when he said the following regarding prisoners of war: "I like people that weren't captured."

"I'd like to see him retract that statement. Not about me, but about the others," McCain said.

When asked what he likes about Trump's foreign policy, he said, "well, I think American leadership, he emphasizes that and I think that's important."

"This president (Barack Obama) doesn't want to lead. Hillary Clinton was secretary of state for four years - tell me one accomplishment that she can point to besides she flew more miles than any other secretary of state in history," he said in a broadside on the Democratic frontrunner.