A State Department spokesman said Thursday the agency was not aware Hillary Clinton relied exclusively on a private email network and referred questions about her email use to the Democratic front-runner's campaign.

In a move that marked a departure from months of defending the former secretary of state's actions, State Department spokesman Mark Toner said he did not know if her email arrangement was "specifically prohibited" but noted it "was strongly discouraged."

"Across the board — and we have acknowledged this — there was only a partial understanding of how much Secretary Clinton relied on personal email, and we just did not have a complete picture and because of that, I think no one undertook the steps to address that," Toner said during an agency briefing.

His comments came one day after the results of a year-long inspector general audit cast doubt on many of Clinton's past claims, including the fact that "everything [she] did was permitted."

The State Department last year said Clinton's personal email use was made public shortly after Clinton left the agency.

"The account's existence had been known publicly since March 2013," said former State Department spokeswoman Marie Harf during a briefing last spring.

"I would also point out that the notion that she had this email account is certainly not news; it's been reported on for more than two years at this point," Harf said during another briefing.

But Toner was forced to confront the agency watchdog's findings that top State Department officials "did not — and would not — approve her exclusive reliance on a personal email account to conduct Department business."

In a statement on her campaign website, Clinton asserts that "her usage was widely known to the over 100 State Department and U.S. government colleagues she emailed, consistent with the practice of prior secretaries of state and permitted at the time."

Toner suggested during Thursday's briefing that the only officials who were aware of her use of a private server were no longer employed by the agency but by Clinton's political campaign.

Although Toner could not answer questions about whether Clinton violated any rules given the inspector general's conclusion that she had, Harf said with confidence last year that Clinton had done nothing wrong.

"There's no prohibition on using this kind of email account," Harf argued in 2015.