A prominent Thai protest leader was taken to hospital late Friday from a Bangkok police station as chaos erupted after he and two others were released on bail over sedition charges.
Panupong "Mike" Jadnok appeared to be unconscious as he was loaded into an ambulance. Local media said he fainted after being subjected to a "chokehold" by plainclothes police.
He, Panusaya "Rung" Sithijirawattanakul and Parit "Penguin" Chiwarak -- in custody since mid-October -- are among the best known faces of Thailand's pro-democracy movement.
Protesters have demanded reforms to the country's monarchy and for Prime Minister Prayut Chan-O-Cha -- the former military chief who staged a 2014 coup -- to resign.
The student-led rallies, which have been going almost daily for months, are also calling for a rewrite of the military-scripted constitution and an end to alleged government harassment of political opponents.
After a court ordered the release of the three activists, police apparently were considering outstanding arrest warrants against them late Friday.
Parit, shirtless and with a buzz cut, dared officers to re-arrest him as he addressed a crowd of about 300 supporters outside the station, who sang songs.
"The iron bars can imprison the stars but not the starlight. In my heart, I still have faith in the people. The wind of change, the wind of democracy has arrived in Thailand," he said.
"We will fight the darkness with the starlight. We will fight evil with flowers. And we will fight guns with white ribbons."
Rung, whose long blonde locks were cut and dyed black during her time in prison, was given a bouquet of flowers by the crowd.
"The movement has to go on. Everybody must recommit to non-violence," Rung said.
"If violence happens, it's not from us. Even though we are getting more frustrated, we must not fall for their ploy."
- Students skip graduation over king -
Among the royal reforms sought are the abolition of the draconian lese majeste law which shields the family from defamation, a clear accounting of the palace's finances, and for King Maha Vajiralongkorn to stay out of politics.
Such calls are unprecedented in Thailand, where criticism of the royal family is taboo.
Scores of students on Friday boycotted their graduation ceremony at Thammasat University, where the king -- who spends much of his time in Germany -- was handing out degrees.
"Some people say it's a once in a lifetime experience (to meet the king). I don't want to meet him. I don't want to pay respect to people like him," one graduate, a 24-year-old who identified himself as Jack, told AFP.
"Why do we need to worship him like a god? I've always asked myself these questions," another graduate, Bowie, told AFP.
An AFP reporter at the scene said the number of students present was visibly smaller than in previous years.
Thammasat University has a reputation for liberal views and was the scene of a bloody crackdown on pro-democracy protesters in 1976.
University officials did not immediately reply to a request for comment.
The king was expected to attend another graduation ceremony on Saturday, and Prayut issued a warning to students not to step out of line.