Sen. Bob Corker (R-Tenn.), the ranking Republican on the Senate Foreign Relations Committee, said Sunday that questions about former Nebraska senator Chuck Hagel's (R) "temperament" will be raised during his Senate confirmation hearings.

"I think another thing, George, that's going to come up is just his overall temperament, and is he suited to run a department or a big agency or a big entity like the Pentagon," Corker said on ABC's "This Week With George Stephanopoulos."

"I think there are numbers of staffers who are coming forth now just talking about the way he has dealt with them," said Corker, who noted that he recently spoke with Hagel. "I certainly have questions about a lot of things. I begin all of these confirmation processes with an open mind."

President Obama's nomination of Hagel to lead the Pentagon prompted pushback from some Republican senators who have expressed concerns about the former senator's positions on some issues.Hagel's past statements about Israel, the Iraq War and Iran, among other things, stoked the resistance. Corker said he also has questions about Hagel's "nuclear posture views."

Appearing on the same program, Sen. Jack Reed (D-R.I.), who sits on the Senate Armed Services Committee, defended Hagel's record.

"And one of the things interesting about this issue of temperament there, I know there's a close relationship between the president and Chuck Hagel," Reed said. "I've traveled with them. I understand it, but I also understand that Chuck has the wherewithal and the ability to speak truth to power. He's demonstrated that throughout his entire career."

On "Fox News Sunday," Sen. Kelly Ayotte (R-N.H.) said she is "very troubled" by Obama's decision to nominate Hagel. While she stressed that she has not made up her mind about whether she will vote to confirm him, Ayotte said Hagel's hearings will be "very consequential."

On the same program, Sen. Richard Blumenthal (D-Conn.) said he believes Hagel will be approved by the Senate.