Security was tightened at the Criminal Court on Thursday ahead of the arrival of four activists arrested by police on Wednesday on charges arising from recent anti-government demonstrations.
Police were deployed at the court about 8am. Small groups of supporters also began showing up.
Human right activists Arnon Nampa, Buramee Chairat, Suwanna Tanlek and Korakot Saenyenphan were arrested on charges of inciting public unrest and other offences
Arnon, a lawyer who first called for reform of the monarchy at a Harry Potter-themed protest, was arrested in front of the Criminal court on Wednesday night.
He was detained overnight at Chana Songkhram police station. The three others were held at Samran Rat police station for their roles in a demonstration on Aug 3.
Police were to ask the court to extend their detention for another 12 days.