We still do not know the identities of Bombay’s attackers, nor which group they belonged to, not even what their demands were. But in one significant measure they have already achieved a major objective by their three-day reign of terror against Indian civilians, foreign tourists and Orthodox Jews in a city better known for culture, trade and entertainment.

After seven years of painstaking rapprochement between India and Pakistan, relations between the two dominant, nuclear-armed states of South Asia are once again seriously at risk. This not only threatens to destabilise the entire region but could also set back the West’s fight against al-Qaeda, the Taleban and other Islamic militants operating in Pakistan and Afghanistan.

The Pentagon began to look afresh this year at the war in Afghanistan, where USled forces are struggling to contain a growing insurgency by the Taleban. One conclusion was that the war could not be viewed exclusively as an Afghan problem. It also involves the Pashto-speaking areas across the border in Pakistan’s lawless tribal territories, where various groups linked to al-Qaeda are operating under constant attack by US drones.

General David Petraeus, the former US commander in Iraq and now in overall charge of US forces in the region, is convinced that the best way to succeed in Pakistan lies through India. If the ruling establishment in Islamabad and the Pakistani people in general conclude that the main threat to their fragile country comes from militant Islam, rather than their traditional enemy India, then the war is close to being won.

Times Archive, 1911: The expansion of Bombay

Bombay stands unchallenged as the great commercial capital of India, distinguished by its enterprise, sobriety of thought, and unity of endeavour

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• The name "Bombay"

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• Pakistan offers help, but is prime suspect

Somebody else came to the same conclusion this week when they ordered the attack on Bombay. Plunge India and Pakistan back into a state of war and millions of young Muslims in the region could be mobilised in a new jihad. Kashmir could once again become a flashpoint. Pakistan might be forced to reduce or withdraw its forces fighting in the tribal areas and turn its attention to India.

There is still no evidence that the commandos in Bombay, also known as Mumbai, had this goal in mind. But it came as little surprise that the young men leading the attack had orders to capture and kill as many citizens of America and Britain as possible, the two countries at the forefront of the military mission in Afghanistan.

What is crucial now is the impact that the raid will have on India. Yesterday India’s leaders, officials and members of the security services increasingly blamed Pakistan for the carnage. They argued, with some justification, that an operation on this scale could have been executed only with the training, funding and support of an outside power. The Indians believe that the boat carrying the gunmen sailed from the Pakistani port city of Karachi and that at least one of the dead assailants was a Pakistani. Indian Intelligence also intercepted mobile telephone conversations between the gunmen and their supporters abroad, again linking them to Pakistan.

The main suspects for the attack are the shadowy organisations Lashkar-e-Taiba (LeT) and Jaish-e-Mohammed, militant Islamic groups fighting for the independence of Kashmir. LeT was banned in Pakistan but still operates as a political force under a different name. There is evidence that elements within Pakistan’s powerful security establishment continue to support it.

Yesterday Islamabad was at pains to deny any involvement in the operation and to defuse the crisis. It took the unprecedented step of dispatching Lieutenant General Ahmed Shuja Pasha, the head of the notorious Inter Services Intelligence (ISI) agency, to help with the investigation.

To some Indians this may seem a little like inviting the main suspect in a murder case to join the police hunt. India has already accused the ISI of masterminding a suicide bomb attack against the Indian Embassy in Kabul in July, which killed 41 people.

Nevertheless, India and the West have little choice but to cooperate. President Zardari, the newly elected Pakistani leader, is struggling to build a civilian government in an increasingly dysfunctional country. His subordinates in the security services might well be trying to intensify regional tensions and undermine his position.

If Mr Zardari goes, the deaths of 143 people in Bombay this week may just be the beginning.

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