McCain, who is the front-runner for the Republican presidential nomination heading into the Super Tuesday primaries, was referring to comments made by five-term Mississippi Sen. Thad Cochran and former Sen. Rick Santorum (Pa.).

“The thought of his being president sends a cold chill down my spine,” Cochran had told The Boston Globe after his endorsement of McCain’s main rival, former Massachusetts Gov. Mitt Romney. “He is erratic. He is hotheaded. He loses his temper and he worries me.”

Santorum, another Romney supporter, has also raised McCain’s temper as a reason not to support him.

The Arizona senator hit back hard at his critics when he was asked about their comments on NBC’s “Today Show.”

“And in all due respect to a couple of those people that are criticizing me, they’re not the most respected members of the United States Senate, to be honest with you,” McCain said, noting that he has a lot of support among his colleagues.

Cochran’s office did not immediately respond to a request for comment.