The exits link the station to popular shopping malls in the area.
The commotion was reportedly caused by members of the anti-monarchy group, Thaluwang, and the pro-monarchy People’s Centre to Protect the Monarchy group.
The anti-monarchy group had gathered in the walkway connecting the train station to Siam Paragon mall on Saturday morning. They were rallying to support the action of activist Tantawan “Tawan” Tuatulanon, who had allegedly honked at and tried to join the convoy of Her Royal Highness Princess Maha Chakri Sirindhorn on Makkasan expressway on February 4. Her actions sparked outrage on Thai social media.
The rally was met with opposition from members of the People's Centre to Protect the Monarchy group. The clash quickly escalated from verbal to physical confrontation as the pro-monarchy group tried to expel Thaluwang members from the BTS connecting walkway. Siam BTS station is one of the busiest in the city.
Police officers from Pathum Wan station tried to break up the fight, which lasted for about 20 minutes, according to witnesses.
At around 1pm, Tantawan and anti-monarchy protestors gathered in front of Pathum Wan police station to file assault charges against members of the People's Centre to Protect the Monarchy group.
Police allowed the group to enter the station and put up a steel fence at the station’s entrance to prevent any further confrontations.