Police on Tuesday arrested four student leaders allegedly involved in a series of demonstrations.
Arnon Nampa, Suwanna Tanlek, Parit Chiwarak and Piyarat Jongthep presented themselves at Nang Loeng police station to acknowledge charges in relation to a rally in front of the Royal Thai Army Headquarters on July 20.
The charges include sedition, illegally entering into a computer system data related to national security, violating the Emergency Decree and Communicable Disease Act and using loudspeakers to promote their cause without permission.
Mr Arnon said their previous arrests were part of the government's strategy to intimidate them but they would continue their fight against the Prayut Chan-o-cha administration.
He was then taken to Klong Luang police station in Pathum Thani province for further questioning, while the other three were released.
Mr Piyarat said they faced a total of six charges but they neither admitted nor denied them, saying only the latest rally in front of the army headquarters was not prolonged and the demonstrators had not obstructed traffic.
Mr Parit said the government was using Covid-19 as an excuse to prevent people from gathering and confirmed they would press ahead with a mass rally planned for Sept 19.
Mr Arnon and "Mike" Panupong Jadnok, who had been arrested in Rayong for holding up a placard protesting against the premier, were later taken to the Thanyaburi Provincial Court in Pathum Thani province, where police asked the court for permission to detain them pending further inquiries.
The two other students were later released without a bail bond but with conditions.
More than 100 police officers provided security at Thanyaburi Court. Only Mr Arnon, Mr Panupong, their lawyers and some reporters were allowed to attend the proceedings.
Meanwhile, pro-democracy activist Jatupat "Pai Dao Din" Boonpattarasaksa has burned a summons for him to report to Khon Kaen police on Friday, declaring it was merely intended to intimidate him.
Mr Jatupat, 29, was taking part in an anti-government rally attended by 500 people in Muang district on Monday night.
The rally was held by the Northeastern People's Alliance for Democracy on open ground in front of the Democracy Monument on Srichan Road in Muang district.