Hillary Clinton's claim that she was unaware top secret documents on her private email server were highly classified took a hit on Friday, with the revelation of a State Department contract she signed in 2009.

The 'Sensitive Compartmented Information Nondisclosure Agreement,' which Clinton inked during her second day as Secretary of State, declared that she was personally responsible for determining if sensitive documents in her possession were classified at the government's highest level.

'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.'

SCI – Sensitive Compartmented Information – is the highest level of 'top secret' classification, applying to information so sensitive because of the sources and methods used to obtain it that it can only be viewed in a special room, hardened against electronic eavesdropping, constructed for that purpose.

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UH-OH: Hillary Clinton signed an agreement with the State Department in 2009 taking responsibility for knowing which information was classified at the government's highest level

EMAILING: Clinton's home-brew private server housed tens of thousands of work emails, hundreds of which have since been classified – including a few at the 'Top Secret / Sensitive Compartmented Information' level

The agreement Clinton signed in 2009, which warns against 'negligent handling' of state secrets, conflicts with her more recent positions on the presidential campaign trail.

Clinton has said none of the hundreds of classified documents found among emails on her unsecured server were classified at the time she sent or received them, and suggested that without a marking from intelligence officials, she wasn't expected to know what is classified.

The libertarian Competitive Enterprise Institute think-tank obtained the document with Hillary's signature, which the State Department declassified on Thursday, and gave it to the conservative Washington Free Beacon.

'I have been advised that the unauthorized disclosure, unauthorized retention, or negligent handling of SCI by me could cause irreparable injury to the United States or be used to advantage by a foreign nation,' the agreement Clinton signed states.

The U.S. Intelligence Community's inspector general has said two of the Clinton emails released by the State Department so far in complying with a federal judge's order contained SCI-level information, and had to be sanitized by experts before they could be published.

A spokesman for Hillary's presidential campaign did not respond to DailyMail.com's request for comment on Friday.

But the text of the agreement spells out plainly that Clinton agreed she was responsible for seeking help if she wasn't clear about what was classified at the SCI level.

It also spelled out what might happen if she broke the terms of the contract.

'I have been advised that any breach of this Agreement may result in my termination of my access to SCI and removal from a position of special confidence and trust requiring such access,' the agreement reads, 'as well as the termination of my employment or other relationships with my Department of Agency that provides me with access to SCI.'

TROUBLE AHEAD: The new revelation comes as Clinton appears to be coasting in the Democratic presidential primary

'In addition,' she agreed, 'I have been advised that any unauthorized disclosure of SCI by me may constitute violations of United States criminal laws, including provisions of Sections 793, 794, 796, and 952, Title 18, United States Code; and of Section 783(b), Title 50, United States Code.'

'Nothing in this Agreement constitutes a waiver by the United States of the right to prosecute me for any statutory violations.'

Government officials who sign the same document Clinton signed acknowledge 'agree that I shall return all materials that may have come into my possession or for which I am responsible because of such access, upon demand by an authorized representative of the United States Government or upon the termination of my employment.'

Clinton never returned her email server to the federal government. She housed it in her Chappaqua, New York home while she was America's top diplomat, and then moved it when she left the Obama administration – entrusting it to a Colorado company that was not cleared to handle SCI-level documents.

The State Department acknowledged in September that Clinton's home-brew server also was never authorized to handle such information.

The FBI is currently investigating Hillary's email mess, in an information dragnet that has also roped in her former chief of staff Cheryl Mills and current top campaign aide Huma Abedin.