Cloth banners with the message in English "Free Patani - Patani is not Siam" were displayed and balloons carried aloft the flag of the Barisan Revolusi Nasional (BRN) separatist movement in many areas in the four southernmost border provinces on Sunday.
Police said the display was symbolic, marking the 62nd anniversary of the BRN, a Muslim separatist movemen seeking autonomy from Thailand.
The cloth banners were found early on Sunday at locations all over Pattani, Yala and Narathiwat and in four districts of Songkhla - Sabayoi, Thepha, Chana and Sadao.
Village volunteers were assigned by security officials take them down
About 5.30pm, BRN flags began appearing in the sky, held aloft by ballons, at 35 spots - 10 each in Pattani, Yala and Narathiwat and five in Sabayoi, Thepha, Chana and Sadao districts of Songkhla.
The BRN website claimed responsibility for the cloth banners, saying it was a symbolic gesture marking the 62nd anniversary of its founding.
It said the BRN stood firm on its promise to liberate "Patani" from Thailand.