The march began at Bangkok's Thammasat University, a traditional hotbed of discontent.

Several dozen students briefly rallied against the coup at Thammasat University, according to social media posts.

Anocha Suwichakornpong's formally-daring second feature begins as a film about making a film about the 1976 Thammasat University Massacre.

The pair were arrested in August over a satirical play they put on more than a year earlier at Bangkok's Thammasat University.

The plainclothes men showed up late at night near Thammasat University in Bangkok, casing out the residence where the student activist slept.

The prison term was raised to 15 years after 1976 student protests at Thammasat University were crushed.

Saturday's student-led demonstration moved from the campus of Thammasat University to a park next to a grand palace used for royal ceremonies.

The monarchy remains a sensitive subject in Thai society and Monday's protest prompted a public statement by Thammasat University apologising for the event.

But Thai political historian Charnvit Kasetsiri at Thammasat University said: How can he bring reconciliation when he is a party in the conflict?

Thammasat University said last week it would not allow the gathering on its campus, but protesters said they were sticking to their plan.

Protesters holds up signs during a brief protest against military rule at Thammasat University in Bangkok June 1, 2014.

Slideshow (5 images) About 3,000-4,000 protesters chanted "Long live democracy" at Thammasat University on the outskirts of Bangkok on Monday night.

Sept. 19 - Thousands protest at Thammasat University in Bangkok on the anniversary of the 2006 coup that overthrew populist prime minister Thaksin Shinawatra.