Chapel Hill, N.C. — A University of North Carolina at Chapel Hill vice chancellor resigned Monday amid an internal investigation into his travel expenses.

Matt Kupec was employed by UNC for over 20 years, and served as vice chancellor for advancement for 16 years, according to the university.

The university's internal auditor is looking into all of Kupec's travel-related expenses, but has not yet determined if any violations occurred. 

Details of the allegations against Kupec were not released.

"This is a difficult day," said UNC Chancellor Holden Thorp. "Matt has made significant contributions over the years, raising billions of dollars for the university. However, these are serious issues that require a thorough investigation."

Kupec released a statement late Monday about his resignation, but did not mention the allegations against him.

"I will miss you all, but in my heart, I will always be a part of the Carolina family," he said.