Tourist centres have been closed in many districts, including Kottayam and Thiruvananthapuram, and a night travel ban has been imposed in the hilly areas of Idukki district.
Discounting any terror link, the Kerala police on Sunday took a man into custody for allegedly planting crude explosive material in the cargo-hold of a Kingfisher aircraft here last week in order to implicate security personnel.
The Kerala High Court on Wednesday issued notice to India cricket captain Virat Kohli and the state government in a plea seeking ban on online gambling in the state.