NEW DELHI, Sept 4: Nearly 36 years after it dispatched theSeventh Fleet to the Bay of Bengal with an implied warning of a nuclear assault on India, a US armada began naval exercises on Tuesday with India and three Pacific allies, and the threat this time is being felt by China.

The exercises have divided the country sharply, with the communist-led Left Front launching nationwide protests on Tuesday.

Twenty-seven ships and submarines from the United States, Australia, Japan and Singapore will join seven from host India off the Andamans archipelago in the Bay of Bengal for the six-day manoeuvres.

The biggest ever Naval flotilla in action will test the joint capabilities in a multi-threat scenario like missile, submarine and aerial attacks, officials said. China has expressed its disapproval of the exercises although the participants say it is not in any way a move to encircle it.

Reports said no live ammunition would be let off but missile,submarines and air tactics would be simulated and recorded in themanoeuvres in the Bay of Bengal lasting five days.

The war-games being held just 40 to 50 nautical miles off the Myanmar Coco Island would also work out joint manoeuvres to deal with sea piracy and sea terrorism.

The exercises have divided the country vertically, with the communist-led Left Front launching nationwide protests.

To mobilise people and organise a national movement against the naval exercises two massive columns — one from Kolkata, led by CPI general secretary A.B. Bardhan, and another from Chennai, led by CPI(M) general secretary Prakash Karat — were flagged off on Tuesday. The day also witnessed rallies and demonstrations all over the country.

Veteran CPI(M) Polit Bureau member Jyoti Basu too flagged off the march from Kolkata.

As the naval exercises are to be held off the coast of Visakhapatnam, both columns will traverse the coastal areas and reach Visakhapatnam for a rally there on Sept 8. The State units of the Left parties in West Bengal, Orissa, Andhra Pradesh and Tamil Nadu are chalking out the programme.

The naval exercises have followed a raging controversy over the US-India nuclear deal, which, again, has been opposed by the Left Front. Prime Minister Manmohan Singh says he wants the deal at any cost, which includes a serious threat to his minority government shored up by the Left Front.

The exercises, stretching from India’s eastern coast to the Andamans near Indonesia, will include super-carriers USS Nimitz and USS Kitty Hawk of the US Navy’s Pacific fleet and India’s lone aircraft carrier, the INS Viraat.

Indian Air Force’s maritime Jaguar deep penetration strike aircraft would, for the first time, be part of the concentrated action by war-planes and warships.

Warnings have been sounded to commercial ships to keep off the exercise path, sources said.

Over 160 fighter aircraft, 20 to 30 prowler air jammers, 6 to 8 E2C Hawkeye would constantly be in the air during the war games, be it day or night, along with countless number of armed and reconnaissance Unmanned Air Vehicles (UAVs).

US President Richard Nixon had sent the Seventh Fleet, including the nuclear-capable USS Enterprise, to the Bay of Bengal to successfully browbeat India in its 1971 war with Pakistan.