Hillary Clinton's presidential campaign is playing major defense against the mounting criticism of her use of a private email server when she was secretary of state.

The 2016 hopeful has faced ongoing criticism for allegedly storing classified material in a private email server while she was working under the Obama administration. Critics say this may have put national security secrets at risk. Her use of the server, which was maintained by a small Denver company and stored at a secure data center in New Jersey, has prompted an FBI counterintelligence investigation.

Several top aides, surrogates and strategists from the Clinton camp were sent out to address the matter in media rounds on Wednesday. They also held a conference call with reporters.

"I think, if you've seen over the last couple of weeks, we have changed our strategy, in that we are trying to do more education through phone calls like this, through television appearances, through emails that we send directly to our supporters," Clinton communications director Jennifer Palmieri told reporters on Wednesday, reports Politico. "We do think people have concerns and questions, and it's really confusing and we want to answer them."

According to the Clinton camp, the criticism is a result of a hyper-partisan political environment and an overwrought media. They also argued that the Democratic presidential frontrunner did no wrong; the email contained no information that jeopardized U.S. interests, and she's done everything she can do in hindsight.

James Carville, a long-time political adviser to Bill and Hillary Clinton, told MSNBC the controversy is being fueled by "mostly stupid media people talking to other stupid media people, making stuff up and spinning themselves up on something that's not gonna amount to a hill of beans."

Meanwhile, on Bloomberg, Palmieri said the former U.S. senator hadn't meant to hide anything by using a private server, rather she "really didn't think it through," reports CNN.

At the same time, the campaign tried to down play the disclosure by arguing the material had been retroactively classified by U.S. intelligence agencies out of caution.

"She was at worst a passive recipient of unwitting information that subsequently became deemed as classified," Clinton's campaign spokesman Brian Fallon said, reports The Wall Street Journal.

The former first lady also insisted it is her right to keep personal emails private.

"They can do whatever they want to with the server to figure out what is there and what is not there," Clinton said of the DOJ investigation into her emails. "That is for the people investigating it to try to figure out. But we turned over everything that was work related -- every single thing. Personal stuff, we did not, I had no obligation to do so. And didn't."

She added, "In retrospect, this didn't turn out to be convenient at all and I regret that this has become such a cause celebre. But that does not change the facts. The facts are stubborn -- what I did was legally permitted."