A day after Hillary Clinton started her job as secretary of state in 2009, she signed an agreement stating she was aware that "negligent handling" of classified information could jeopardize national security, also acknowledging that it was ultimately her responsibility to determine which information may be classified, reported the Washington Free Beacon.

"I have been advised that the unauthorized disclosure, unauthorized retention, or negligent handling of [Sensitive Compartmented Information] by me could cause irreparable injury to the United States or be used to advantage by a foreign nation," reads the Sensitive Compartmented Information Nondisclosure Agreement, which also details possible criminal penalties for the unauthorized disclosure of such classified information.

The FBI is currently investigating whether Clinton jeopardized classified information by using a private home-based email server during her tenure as secretary of state, which was set up her home in Chappaqua, N.Y.

So far, the U.S. intelligence community's inspector general said he found at least two emails on Clinton's system that are considered "TS/SCI," or top-secret/sensitive compartmented information - one of the highest levels of classifications, reported The Associated Press.

Further, the Democratic presidential front-runner's server was not authorized to handle such sensitive information, the State Department said in September.

Clinton has defended her sending of emails containing classified information and their unauthorized storage by insisting that none of the messages contained information marked classified at the time they were sent, but the language of the nondisclosure agreement makes it clear that Clinton was responsible for determining what information could have been considered classified.

"I understand that it is my responsibility to consult with appropriate management authorities in the Department ... in order to ensure that I know whether information or material within my knowledge or control that I have reason to believe might be SCI," the agreement says. "I further understand that I am obligated by law and regulation not to disclose any classified information or material in an unauthorized fashion."

A copy of the agreement was obtained by the Competitive Enterprise Institute in a Freedom of Information Act request and given to the Washington Free Beacon.