New Delhi, Jan. 9: Nearly two-thirds of the Indian Navy, including warships, helicopters and a submarine, is at sea for “operations” since the Mumbai attacks in November in which terrorists invaded the country’s financial capital in inflatable rafts and wreaked havoc.

The Indian Navy has about 120 major fighting vessels.

A bulk of India’s warships, many of which have been re-deployed from the east coast to the western seaboard, are currently engaged with the Indian Army and the Indian Air Force in a war game in the Arabian Sea that is testing a new offensive doctrine for amphibious operations. Pakistan is watching this drill with some nervousness since the terror attacks have led to a diplomatic stand-off between the two countries.

The deployment was planned before the Mumbai attacks. But a suspicion that a concentration of forces can flare up into a conflict adds to the tension.

The war game named Triveni is centred on an island in the Lakshadweep and Minicoy group. “About 75 per cent of our major platforms are currently deployed operationally,” a senior navy source said here today. Among these is the INS Jalashwa, the navy’s latest major acquisition, a US-origin landing platform dock that can carry up to 1,000 troops, tanks and other weaponry.

The role of the navy was called to question since the attackers in Mumbai came in from the sea after sailing from Karachi, intelligence reports have said.

But the navy has been staunchly defensive of its role. Its chief, Admiral Sureesh Mehta, had sought to absolve his force of all blame and said it did not get any “actionable intelligence”.

But since the terror attacks, the navy has deployed a bulk of its fighting ships to the western seaboard. Another large ship, a destroyer, is patrolling the Gulf of Aden in anti-piracy operations.

All of Pakistan’s navy is concentrated in the Arabian Sea to India’s west. In an India-Pakistan war scenario, Pakistan fears an attack on its coast by Indian forces. In the 1971 war, the Indian Navy had blockaded Karachi port and bombed the city.

Exercise Triveni, the first of its kind, is expected to be wound up over the weekend after a fortnight in which specialised units of the army practised “amphibious landings” — generally interpreted as an offensive/assault tactic — with the navy and the air force on one or more islands in the Arabian Sea.

Triveni is the first major war game involving all the three armed forces and the coast guard since the adoption of a “Joint Amphibious Warfare Doctrine” by the services in September 2008.

But between 2004 — since the services began working on the doctrine — and 2007, the navy has been engaged in “amphex” (amphibious exercise) scenarios both in in-house drills as well as with mainly western forces. The last drill was named Tropex.