Former Delaware Senate candidate Christine O'Donnell sought to discredit a federal investigation into her alleged misuse of campaign funds, denouncing it as a "thug political tactic."

In her first interview since reports emerged that federal authorities began a criminal investigation into whether she used campaign funds for personal expenses, O'Donnell (R) said she did nothing improper.

"No. There's been no impermissible use of campaign funds whatsoever," O'Donnell told ABC's "Good Morning America" program Thursday. "You have to look at this whole thug politic tactic for what it is. We have heard of no investigation. The AP has been tipped off before [us].

"I am confident we have always done everything to comply with all the rules and regulations, and I'm confident that we will be cleared of any charges," she added.

The Associated Press reported Wednesday, citing an anonymous source, that two FBI agents and two federal prosecutors have begun the probe. 

O'Donnell's comments largely echo a statement released Wednesday by her campaign that portrayed the investigation as politically motivated.

The Tea Party favorite pulled off a stunning upset of veteran Rep. Mike Castle (R) in the GOP Senate primary, raking in a state-record $7.3 million-plus fundraising haul.

But the conservative activist was dogged with questions about her alleged disbursement of $20,000 from her campaign account to pay for her rent and other personal expenses.

The non-partisan watchdog group Citizens for Responsibility and Ethics in Washington (CREW) filed a complaint with the Federal Election Commission in September over the payments. O'Donnell accused the group of having a liberal bent that influenced their decision. 

"The woman leading the CREW [Citizens for Responsibility and Ethics in Washington] complaint is a former [Joe] Biden staffer who is so far to the left that she's to the left of most leftists," she said.

"You don't need a tipster to show that this was politically motivated," O'Donnell noted. "We were informed that the Delaware political establishment was going to use every resource available to them, including launching phony investigations ... tying me up with lawsuits to make sure I can't move forward politically.

"I even expect more things to come, that's their tactic," she added.

O'Donnell lost the Senate race to Democrat Chris CoonsChristopher (Chris) Andrew CoonsLawmakers target link between wildlife poaching, terror groups Senate adds members to pro-NATO group Sunday shows preview: Trump readies for meeting with Putin MORE, who is filling Biden's former seat.