In this Dec. 16, 2007 file photo, former Sen. Bob Kerrey introduces Hillary Clinton during a campaign stop in Council Bluffs, Iowa. (Reuters)

A fellow Democrat ripped Hillary Clinton on Friday over her personal email use while secretary of state, accusing her of doing an unprecedented "end-run" with her home server set-up. 

Bob Kerrey, a former Democratic Nebraska senator, made the comments on Fox Business Network's "Mornings with Maria." 

"I believe what the secretary did was to say ... 'I want to do an end-run around for you. I'm going to set up a server in my home.' Nobody's ever done that before," he said.  

Kerrey is a former Nebraska governor and senator who left Congress in 2001. He also served on the 9/11 Commission. Though not a formal adviser, he's had conversations with the Clinton campaign for her 2016 bid. 

Yet he was blunt in his criticism of the presidential candidate's actions as secretary of state. 

Kerrey questioned Clinton's previously stated rationale for opting to use only one address. 

"It wasn't because she didn't want carry two cellphones around. She's secretary of state, for God's sake. Give me the red one, give me the blue one. Who the hell cares?" 

Kerrey also took issue with claims that the server that housed the messages was secure. 

"She said don't worry about it, I got Secret Service guarding my house," Kerrey told FBN. "Secret Service doesn't do cybersecurity. Physically guarding a server doesn't prevent it from being hacked. You're secretary of state -- you decide what the security is going to be." 

The comments come after Clinton apologized for her actions for the first time, saying her decision to use only one personal system was a "mistake." 

But in a message posted on Facebook, she maintained her use of a personal account "was aboveboard and allowed under the State Department's rules" and "nothing I ever sent or received was marked classified at the time."