Mumbai/Washington, Nov.28 : Though intelligence and security officials are cautious about arriving at early conclusions on the Mumbai terror strikes, they have admitted that planning for it could have taken place in Pakistan, and its execution was carried out with the help of an Indian affiliate.
They also suggested that the scale of the attacks and the planning suggests the role of the Lashkar-e-Toiba (LeT), and a pulling of strings from behind by al Qaeda.
If LeT has indeed carried out the attacks, it would be the first time the terror group has singled out Westerners, say counter-terrorism experts.
It makes it even more likely that al-Qaeda was pulling the strings, they add.
The only claim of responsibility so far is from the Deccan Mujahideen, a previously unheard-of group. Some experts believe that it could be an offshoot of the Indian Mujahideen, which has claimed responsibility for a series of multiple bomb attacks this year.
However, the complexity of the Bombay attack suggests the perpetrators were trained by a military group or established Islamist organisation.
"Given the scale and sophistication, it appears to have been carried out by some group based in Pakistan," The Times quoted Kanchan Lakshman, of the South Asia Terrorism Portal, as saying.
LeT, which is based at Muridke, near Lahore in Pakistan, has networks throughout India and its leadership has close links with core al-Qaeda figures living in Pakistan.
The attack was unusual in that it relied not on suicide bombers but on heavily armed "fedayin", or suicide attackers, who typically take hostages and shoot it out with their opponents before sacrificing themselves.
That, according to experts, is a trademark of LeT or Jaish-e-Mohammed - the other, smaller, group blamed for the 2001 Indian parliament attack.
Peter Bergen, a terrorist expert at Harvard University, said: "You know when you go in that you are going to die. In that sense, it is a suicidal, not a suicide, attack."
Bergen said that while planning for Wednesday's attack probably took place in Pakistan, the plotters probably used a local group in Bombay to execute it.