Two Indians and three Sri Lankan nationals were arrested by the Coast Guard after a patrol ship intercepted their boat 'Rama Jayam' off the Kodikarai coast in Nagapattinam district late on Tuesday night.

The arms seized from the boat included an AK 56 rifle, 124 rounds of live ammunition, five hand grenades, a 7-kg suicide jacket, 7 kg of white chemical powder and eight drums containing 55 litres of liquid chemical, which could be used for making ammunition, Coast Guard Regional Commander Rajendra Singh told reporters in Chennai.

A satellite phone for communication along with sufficient food provisions was also found on board, he said adding the detained men were identified as Ramachandran (41) Siva Padmanabhan (43), both Indians, and Arumugam (53) A Purushothaman (28) and Mathaiah (21) from Sri Lanka.

In the second haul, 'Sahayam', a boat carrying "chemicals" meant for making sophisticated mines and grenades, was intercepted and seized off Dhanushkodi coast tonight and three Sri Lankan nationals were arrested.

Coast Guard officials in Rameswaram said that the boat was carrying 123 bags of chemicals, clips, fuse and remote devices for making mines and grenades.

The arrested were identified as Sukumaran (45), Ranjitkumar (31) and Jayakaran (33), all from Mullaitivu in the island nation.

Both the boats were heading for Sri Lanka, the officials said.

"We dont know where they (the items) had been procured, but feel they should have been procured not only in Tamil Nadu but elsewhere and brought to Tuticorin coast," an official with the intelligence wing of the state police told PTI.

The trio arrested on Wednesday had come to Tuticorin only on February 11 and had procured 123 bags of chemicals and other items in just two days.

"It was not possible without the help of local people," a Coast Guard official said.

According to officials, the boat operators had chosen the Dhanushkodi-Talaimannar and Kodikarai-Kangesanthurai routes as they were the shortest routes to reach Jaffna.

All the eight persons were taken to Chennai for questioning, they added.

The officials said though the arrested persons were highly armed, they did not offer much resistance. "It would have been a disaster, had they fired," they said.

Meanwhile, police had been deployed at strength in the islets dotting the Palk Straits. Strangers coming to the Rameswaram coast were being closely monitored.

Meanwhile, Ramanathapuram Congress MLA K Hasan Ali told PTI that he was baffled about the source of such huge quantities of arms.

"Series of explosives haul in the last 15 days..that too in large quantities..all meant for Sri Lanka. Tamil Nadu Government should deal with them with an iron hand," he said.

The MLA, who openly criticised the militants in the island nation, said he himself felt scared.

"The smuggling activities create fear among the people in coastal districts," he said.

Police should have more rescue boats and patrol vehicles in the coastal areas and should be better trained and equipped to deal with the smugglers, he said.