DES MOINES, IOWA (AP) -- Northern Iowa athletic director Rick Hartzell has resigned.

The university says his resignation is effective January 31.

UNI will name an interim AD by February 1 and begin a nationwide search.

Hartzell, who's been AD since 1999, told the Cedar Rapids Gazette that he's been trying to renegotiate certain parts of his contract.

He was seeking a contract extension beyond June 2009. He wanted to report directly to UNI President Ben Allen instead of Vice President Tom Schellhardt, and wanted the athletics department to regain control of the ticket office and facilities management.

Hartzell oversaw tremendous growth in the school's athletic department, both on the field and off. He hired former men's basketball coach Greg McDermott, who led Northern Iowa to three straight NCAA tournaments before leaving for Iowa State, and football coach Mark Farley.

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