The official says 19 of the students all from Cairo's Al-Azhar University were sentenced to five years in prison each. Another defendant got three years.
The official says the 19 were also fined USD 2,860 each for property damages. He spoke on condition of anonymity because he wasn't authorised to talk to media.
Al-Azhar students have been rallying almost daily to denounce the military's ouster of Morsi, who hails from the Muslim Brotherhood group, and the current military-backed authorities in Egypt.