At least 20 pro-LTTE activists were arrested this morning for the attack on an army convoy near Coimbatore a day ago, police said.
Cases have been registered against 200 people belonging to political groups sympathetic to the banned Liberation Tigers of Tamil Eelam (LTTE). The arrested include Periyar Dravidar Kazhagam and Tamil nationalist leader K. Ramakrishnan, police sources added.
Supporters of the Tamil Tigers on Saturday stopped five army trucks carrying ammunition and personnel on way back from training in Secunderabad in Andhra Pradesh. They were on their way to Thiruvananthapuram.
The angry protesters pelted stones causing minor damages to a couple of trucks.
"They (army personnel) were supposed to halt at the unit in Coimbatore for the day. The attack took place just before they reached Coimbatore. There has been no damage (to arms and ammunition) at all," a defence spokesman had said Saturday.
Sri Lanka's war against the LTTE has caused a stir in Tamil Nadu where the group has many supporters for its cause to carve an independent state for minority Tamils in the island nation. The months of combat operations have pushed the Tamil Tigers to a corner.