NEW DELHI (Reuters) - India and Pakistan have ratcheted up their rhetoric over last month’s Mumbai attacks, but analysts say a fourth war between the two nuclear-armed rivals remains unlikely.

Tensions are nonetheless running high after India warned its nationals Friday it was unsafe to travel to Pakistan and Islambad cancelled all army leave, leaving Washington to urge both sides not to increase tensions further.

Another attack on India launched by Pakistan-based militants, however, could see New Delhi act decisively.

Here is a look at some possible scenarios for India in event of war:

POLITICAL

- The Indian government faced widespread voter anger at the security and intelligence failures that led to the Mumbai attacks and must go to the polls by May. A strong response could see people rally behind it.

The opposition BJP has made militant attacks a major campaign issue ahead of the general elections and has already indicated it would back the government if it chose to go to war. However, the BJP has also been criticised in some quarters for being opportunistic in making terrorism an election issue.

India signed a landmark civilian nuclear cooperation deal with the United States earlier this year and might hope its growing political ties with Washington would get a further boost if it hit militant targets inside Pakistan with missiles and fighter jets.

But war would complicate the West’s efforts to stabilise Afghanistan, a major priority for Washington and President-elect Barack Obama’s new administration. Some jihadi groups fighting Indian rule in Kashmir have built ties with al Qaeda and the Taliban in Pakistan’s ethnic Pashtun tribal belt on the Afghan border.

SECURITY

- India lost 8,000 soldiers in the three wars it has already fought with Pakistan and would naturally not want to suffer more casualties if it began significant troop movements to its western border.

In case of war, India’s big concern would be internal security. Maoist guerrillas -- described by Prime Minister Manmohan Singh as the biggest internal security threat -- could be expected to step up attacks, along with rebel groups in the northeast.

As India moves its troops guarding the India-China and Indo-Myanmar borders in the remote northeast to western India, militants could also use the vast gaps left behind to infiltrate into India.

Islamist militant groups could also use this opportunity to enter Indian territory from the fluid border with Bangladesh and carry out suicide strikes to further divert attention.

ECONOMY

- With India struggling to recover from the effects of a global economic meltdown, a war could mean a disaster for the country which, according to economic think tanks, would have to spend an estimated $3 billion on troop movements alone.

There would be an immediate effect on trade, with sea and air routes disrupted. On the other hand, the manufacturing industry would gain as demand for war hardware would increase, providing more employment opportunities.