Additional troops and police were deployed at communities, residences of officials, government offices, and at the celebration of Yala city's shrine and the annual Red Cross fair.
Intelligence agencies issued a warning that insurgents had stolen 13 motorcycles to make motorcycle bombs.
On Monday night, security forces checked all motorcyclists that entered the Yala downtown area.
Yala police chief Pol Maj Gen Krissada Kaewchandee said he instructed police stations to patrol their areas more frequently.