It must be linked to al-Qaida. That was an immediate, simplistic - and probably misleading - response to the attacks on big hotels, seen as western targets, in Mumbai.
Certainly, the terrorists appeared to be Muslim extremists. Although they must have assumed they were going to be killed even though they took hostages, the attackers were not suicide bombers, overt martyrs of the kind we have witnessed elsewhere - in London, Iraq, and now in Afghanistan - since the 9/11 attacks on the US.
A group calling itself the Deccan Mujahideen, which some analysts describe as an al-Qaida affiliate, claimed responsibility for these latest attacks. The group appears to have named itself after a plateau in central south India.
Unlike al-Qaida-inspired extremists, they have made more traditional and more straightforward demands, namely the release of "Muhajideens" held in Indian jails. However, one similarity with al-Qaida tactics is that there was a number of simultaneous attacks.
Two groups, the Indian Mujahideen and Lashkar-i-Taiba (Army of the Pure) have claimed responsibility for attacks in India over the last 12 months, But most of these have been aimed at such vulnerable targets as commuter trains and market places. Those responsible for the latest atacks have different tactics. They had "western" targets in their sights, and they went in fighting - not simply planting bombs and the leaving the area.
One expert was reported today as comparing the attacks to the bombing of the Marriott Hotel in Pakistan's capital, Islamabad, on September 20.
Professor Richard Bonney, the author of Jihad: From Qu'ran To Bin Laden, said the difference was that in Mumbai there were coordinated attacks and westerners were singled out as hostages. He said: "This attack looks more dangerous and better planned, though not directed against possible government targets but economic ones and of course the 'western allies'."
The Indian Mujahideen, described as "home grown miltants", has previously declared "open war" against what it says is 60 years of Muslim persecution in India. Lashkar-i-Taiba has claimed responsibility for attacks protecting at what it calls the Indian occupation of Kashmir.
Dominic Armstrong of Aegis Defence Services, a London-based security firm, said: "Recent attacks by Hindu extremists (some of whom have reportedly been arrested) have been unsubtle and largely against mosques. These attacks look very much to be the work of Islamists, and not Muslims of the more traditional Indian sectarian type, but of a more sinister international flavour, with distinct hallmarks of al-Qaida, although probably at subsidiary/affiliate level".
One issue will be how Pakistan responds, not least to Indian populist accusations that Pakistan is behind all attacks in India, and how much sympathy the new government in Islamabad extends to Delhi.