
The court ruled to grant the police's custody for two days and the nine suspects were booked at Samsen police station.
Earlier, there was a face-off as the protest leaders resisted after the police notified them of charges relating the Sunday's rampage by anti-coup protesters.
Law enforcement authorities and organisers from the Democratic Alliance Against Dictatorship tried to outwit one another in legal tactics.
Police justified the detention citing potential menace to society as grounds while the suspects cried foul for being lured to surrender themselves.
In police's custody are Veera Musigapong, Jatuporn Phromphan, Jakrapob Penkair, Natawut Saikua, Weng Tojirakarn, Wiputhalaeng Patanapumithai, Manit Jitchanklab, Apiwan Wiriyachai and Jaran Ditapichai.
Bound by the Wednesday's court-mediated agreement, the nine reported themselves to police in lieu of facing arrest warrants.
The indictment session took place at the Criminal Court building on Ratchadapisek Road.
After all nine suspects were brought into a court conference room, Metropolitan Police deputy commissioner Maj General Jaet Mongkolhatthi spelled out their two key charges.
The charges are the assembling of more than 10 people with the intent for disturbing peace and the instigation of violence.
Jaet then proceeded to read out a police detention order for further questioning and showed them a writ on the court's approval for remand.
"Police have followed the prescribed procedures on questioning suspects and the detention should not be construed as a back-stabbing tactics because authorities act within the mandate," Jaet's boss Lt General Adisorn Nonsee said.
Adisorn, the Metropolitan Police commissioner, was reacting to a live interview by Jakrapob who immediately made several calls to the media after learning his fate.
Under Article 134 of the Criminal Procedural Code, police are empowered to take any suspects into custody for questioning following the notification of charges.
"Police committed a legal foul play," Jakrapob said, insisting there was no justification for detention since all nine suspects surrendered.
Manit, a retired judge, said he would not leave the court building unless he was granted bail.
Since the order for detention was served inside the court, the suspects took advantage by applying for temporary release.
The entire afternoon became tense while the nine bail applications were being processed.
Anti-coup protesters rallied at Sanam Luang to attack the police move. Some 150 policemen were deployed at the court building to keep peace.