Luangpu Buddha Isara, the leader of the protesters at the Chaeng Wattan site, had to be escorted out of the compound of the Police Club after police fired teargases and water canon at him.
The monk led protesters from the Chaeng Wattana site to the club to protest against the Centre for Administration of Peace and Order at noon.
Protesters removed barbed barriers at 12:20 pm and the monk demanded the CAPO to send representatives to hold a talk with him.
With no one showing up, the monk led protesters to go inside the compound, prompting police to warn them to retreat.
When the protesters continued to move in, police fired water canon and teargases at the protesters, injuring the monk who was standing in the front.
Guarded rushed to escort him out to give first aid treatment.