University Chancellor Holden Thorp and UNC System President Erskine Bowles both telephoned Tancredo to apologize, The (Raleigh, N.C.) News & Observer reported Thursday.
Protesters objecting to Tancredo's views on immigration shouted Tuesday as he tried to give a speech. Students smashed a window a few feet from where he stood and blocked his face with a banner that said, "No One Is Illegal."
The event was cut short due to broken glass and use of pepper spray by police.
The UNC chapter of Youth for Western Civilization, which sponsored the talk, reportedly paid Tancredo $3,000 for the appearance. The group has called on the university to invite the former Republican presidential hopeful back to the campus on the school's dime.