The demonstration, however, turned violent after security forces attacked the roughly 7,000 angry students. Many of the students were forcefully locked in several rooms in the university building.
Students complained against new measures implemented on campus, including separate entrances and exits for male and female students, refusal of entry for students with long hair, short-sleeve shirts, bright-coloured clothes, or sports shoes.
Chants of Bassijis, leave the university could be heard during the rally. The Bassij are hard-line Islamist vigilantes loyal to Supreme Leader Ayatollah Ali Khamenei.
The protestors attacked the office of the security forces, based on the third floor on campus.
They chanted slogans against government support for the new hard-line policies in the university.
During the rally, the students sang several patriotic and revolutionary songs, including Iran, land of the pearls.
Najaf-Abad is in the central province of Isfahan.
