In the wake of seizures of arms and explosives off the Tamil Nadu coast, Defence Minister A K Antony on Sunday asked the armed forces to be alert to the "danger lurking" near the shores and promised bigger ships and more aircraft would be inducted for enhanced surveillance.

"We have to be constantly alert, otherwise there is danger lurking at the sea coasts," he told a press conference after the maiden Fleet Review of Coast Guard ships.

Antony said the Chennai incident, wherein the Coast Guard seized a suspected Liberation Tigers of Tamil Eelam boat with explosives and arms, including an explosive-laden belt used by suicide bombers, could be the "tip of the iceberg."

"There can be several such instances in the vast sea," he said.

His comments come on the heels of National Security Advisor M K Narayanan's remarks that some fictitious companies listed on stock markets in Mumbai and Chennai had been traced to terrorist groups.

Home Minister Shivraj Patil had also said that terrorist groups were making inroads into big cities and operating clandestinely.

Asking the armed forces to be alert, Antony said, "The topmost priority of the Coast Guard and the navy is surveillance of the coastline and the sea.

We will provide them ships and aircraft," he said adding, he has asked shipyards, both state-owned and private, to speed up the construction of vessels.