A team led by Watrap sub-inspector Prakash was checking vehicles when the motorcycle riders tried to turn back after seeing the police. Officers intercepted them and found the explosives in a pouch on the bike.
Police identified two of those arrested as P. Manikandan, 18, and S. Kavirajan, 19, both from Watrap. The three told officers they were carrying the bombs to hunt wild animals in the Western Ghats, according to police; that account has not been independently established.
All three have been booked under the Explosives Act and the Explosive Substances Act. The police account does not state whether anyone was injured or whether further arrests are expected.