Police used shipping containers to block inner Bangkok streets on Thursday morning, ahead of planned anti-government rallies close to Government House and the Grand Palace.
The barricades were placed at Thewet Narumit Bridge on Samsen Road, Wisawakam Naruman Bridge on Nakhon Ratchasima Road, Makkawan Rangsan Bridge on Ratchadamnoen Nok Avenue, Chamai Maruchet Bridge on Phitsanulok Road, Orathai Bridge on Luk Luang Road, in front of the Supreme Court on Ratchadamnoen Nai Avenue, and in front of Wat Mahathat Yuwaratrangsarit on Na Phra That Road.
Police said no one would be allowed to damage the barricades, or to pass through until the rallies end.
Protest leaders have announced plans for several rallies on Thursday, which is Constitution Day, including at the October 14 Memorial on Ratchadamnoen Avenue.