An audit by the State Department inspector general has concluded that former Secretary of State Hillary Clinton violated her agency's own records policy by withholding all of her government-related communications.

"Secretary Clinton should have preserved any federal records she created and received on her personal account by printing and filing those records ... because she did not do so, she did not comply with the department's policies that were implemented in accordance with the Federal Records Act," the watchdog report said.

Clinton has faced multiple investigations into her use of a private server to shield her official emails, including an FBI probe and an internal State Department review.

The inspector general report, which was provided to lawmakers Wednesday, contradicts Clinton's longstanding claim that her personal email network did not break any rules that were on the books at the time.

Clinton and her chief of staff, Cheryl Mills, declined to be interviewed for the report, the inspector general said. Huma Abedin, her deputy chief of staff, also declined to speak with the watchdog.

The report references an "individual based in New York" who worked on Clinton's server without every being employed by the State Department. Such an individual has not been mentioned in previous reporting about the private server Clinton maintained.

State's inspector general only identified him or her as "an advisor to former President Clinton." The individual registered the "clintonemail.com" domain name.

Former Secretary of State Collin Powell, who was also cited in the report for using a private email account on a daily basis, submitted for an interview with the agency's watchdog. Powell pointed to restrictions during his tenure on communicating via email with individuals outside the State Department as his reason for using a personal email account.

The report noted email policies were "very fluid" at the time Powell occupied his post.

"By Secretary Clinton's tenure, the Department's guidance was considerably more detailed and more sophisticated," the inspector general said. Clinton's campaign often points to Powell's private email use as evidence that the Democratic frontrunner operated in a manner to similar to other secretaries.

The inspector general noted Clinton did not seek approval for her personal email network, although she has frequently argued that "everything [she] did was permitted."

If Clinton had asked permission, the watchdog said officials would not have approved "her exclusive reliance on a personal email account to conduct Department business, because of the restrictions...and the security risks in doing so."

State Department officials are typically required to print and file government-related emails in order to maintain a supply of federal records. However, the inspector general said his team "identified one email exchange occurring shortly before Secretary Clinton joined the Department that demonstrated a reluctance to communicate the requirement to incoming staff."

While the audit examined the record-keeping practices of five former secretaries of state, it found Clinton's arrangement to be particularly out of compliance with federal regulations.

Brian Fallon, a spokesman for Clinton's campaign, argued the inspector general had simply confirmed Clinton's claim that she followed a precedent set by past secretaries of state who also used private email accounts.

"Contrary to the false theories advanced for some time now, the report notes that her use of personal email was known to officials within the Department during her tenure, and that there is no evidence of any successful breach of the Secretary's server," Fallon said in a statement.

The report noted Clinton's production of emails to the State Department was incomplete. Clinton's legal team sifted through the roughly 60,000 emails stored on her server and decided which to hand over and which to delete.

The batch of records ultimately provided to the State Department "included no email covering the first few months of Secretary Clinton's tenure—from January 21, 2009, to March 17, 2009, for received messages; and from January 21, 2009, to April 12, 2009, for sent messages. [The inspector general] discovered multiple instances in which Secretary Clinton's personal email account sent and received official business email during this period."

Despite Clinton's repeated statements promising to cooperate with any investigation into her controversial email arrangement, the inspector general noted it sent 26 questionnaires to Clinton's staff and received only five responses.

The report mentions concerns about cybersecurity risks associated with private email use. State's watchdog cited a March 2011 classified memo that was sent directly to Clinton warning of "a dramatic increase since January 2011 in attempts by [redacted] cyber actors to compromise the private home e-mail accounts of senior Department officials."

On the campaign trail, Clinton has dismissed concerns that her private server was ever vulnerable to cyber attacks.

State Department technology officials told the inspector general that "Secretary Clinton never demonstrated to them that her private server or mobile device met minimum information security requirements."