Thai police arrested influential activist Anon Nampa on Wednesday for calling for a protest in favor of reforming the monarchy, according to the CNA television station.
This is the second time 36-year-old Anon has been arrested that same month. The activist is at the head of a movement that in June called for strong protests against the monarchy in Thailand practically every day.
Anon was the first opponent to propose a constitutional amendment to reduce the powers of the royal household and was charged with sedition, a police officer said.
Groups of protesters recently called for the dissolution of parliament, a new Magna Carta and an end to what they see as acts of repression against critics and dissidents in the Southeast Asian country.