Two major protest planned rallies on Bangkok streets on Friday afternoon for the Constitutional Court's ruling on suspended prime minister Prayut Chan-o-cha term in office.
The court is due to start delivering its ruling at 3pm.
The United Front of Thammasat and Demonstration, led by student activists, planned to gather at Pathumwan skywalk, on Pathumwan intersection around 4pm.
At 5pm, the Khana Lomruam Prachachon (Melting Pot Group), led by Jatuporn Prompan and lawyer Nitithorn Lamlua, was due to rally at Ratchaprasong intersection under the slogan “Stop the three 'Pors', Stop Coups, Count Thailand from One’’.
The "three Pors" refers to three retired generals - Gen Prayut, Gen Prawit Wongsuwon and Gen Anupong Paochinda, whose nickname is Pok - who have held the major cabinet posts since the 2014 military coup.
The United Front of Thammasat and Demonstration posted this message on its Facebook page on Friday: "Demonstrate people's power. If the Constitional Court gives its ruling for tyrant Prayut Chan-ocha to continue serving as prime minister, this means that all tyrants will want to stay in power longer. Let brothers and sisters in all areas, all streets and all electric train lines head to the Skywalk at Pathumwan intersection at 4pm''.
Mr Jatuporn posted this message on his Facebook: "Stop the 3 Pors', Stop Coups, Count Thailand from One. Gather at Ratchaprasong intersection at 5pm on Sept 30."
Police deputy spokesman Pol Col Krisana Pattanachaoren said 300 police had been deployed around the Constitutional Court for the ruling announcement. The area around the court has been declared a "safety zone" since Wednesday evening, until Oct 3.