Thai riot police have cleared protesters from outside the prime minister’s office shortly after an emergency decree took effect early on Thursday morning.
Some protesters tried to resist, using makeshift barricades, but they were pushed back, Reuters reports.
Thai Lawyers for Human Rights said three protest leaders had been arrested.
The Thai government brought in the emergency decree to combat large demonstrations in Bangkok. It is thought that protesters confronting a royal motorcade on Wednesday is the main reason for bringing in the decree.
The government said urgent measures were needed to “maintain peace and order”.
In addition to limiting gatherings to four people, the decree effectively shuts down reporting on the protests.
New media restrictions prohibit the “publication of news, other media and electronic information that contains messages that could create fear or intentionally distort information, creating misunderstanding that will affect national security or peace and order”.
The growing student-led protest movement, which began in July, has become the greatest challenge in years to Thailand’s monarchy and government.
Demonstrations at the weekend were some of the largest in years, with thousands demanding change while the police stood by.