MADRID AND BOSTON — As investigators focused Saturday on whether the attacks in Mumbai, India, were the work of a militant group with a history of strikes on the country, the Pakistani government pledged to investigate any evidence of involvement by extremists based on its territory.
Pakistani officials promised to look into the alleged role of "nonstate actors," a phrase generally used to mean militant groups such as Lashkar-e-Taiba, and President Asif Ali Zardari pledged quick action against any individual or group shown to be involved.
But Foreign Minister Shah Mehmood Qureshi told reporters that India had not presented Pakistan any such proof.
U.S. and other Western investigators are supporting efforts by Indian authorities to determine the identities of the attackers, and say they have been briefed on the status of the investigation.
Indian officials said the teams of attackers that struck Wednesday night in the center of India's commerce and film industry had planned to kill 5,000 people. At least one attacker was wounded and captured.
Indian officials said the captured gunman was Pakistani. A senior Western security official, who, like others, discussed the case on condition of anonymity because of its sensitivity, said the gunman was providing leads implicating Lashkar. The group has denied involvement.
"The anti-terrorism squad has got this guy, and they're getting him to spill the beans," the security official said. "He's telling them a lot."
The gunman has been tentatively identified as Ajmal Amir Kamal or Ajmal Amir Qasab from the Faridkot district of Pakistan's Punjab province, said a person close to the investigation. The gunman and a second attacker took part in the shooting assault on a train station and hijacked a police car, setting off a chase during which police shot out the tires, pursued them as they commandeered a private vehicle, and finally cornered and shot the gunman, the Western security official said. The other attacker was killed.
Investigators suspect that a contingent of about a dozen attackers affiliated with Lashkar-e-Taiba traveled by sea from the Pakistani port city of Karachi on a merchant ship, the official said. The investigators suspect the gunmen hijacked an Indian vessel, killed three of the crew members and forced a fourth to steer them to Mumbai, where they killed him, a second Western source said. They went ashore in a rubber Zodiac boat and converged with fellow gunmen, the Western officials said.
Indian intelligence officials believe that a possible trial run occurred in March, but that Indian authorities tracked those suspects with a device placed on their commercial fishing boat, allowed them to complete the test and subsequently arrested them, the sources said.
The paramilitary-style plot reinforces suspicions of Lashkar-e-Taiba, a senior European anti-terrorism official said. Although Al Qaeda has close ties to the Pakistani group, so far the connection to this plot seems indirect at best, investigators say.
In contrast to Al Qaeda's penchant for suicide bombings, Lashkar-e-Taiba has a history of guerrilla or paramilitary raids such as an assault on the Indian Parliament in New Delhi in 2001.
These well-planned, commando-type missions deploy gunmen who expect to die, but first execute complex tasks such as taking hostages and storming buildings. The operatives require more training than suicide bombers, who are often radicalized amateurs chosen mainly for their determination to get up close to a target and die, anti-terrorism officials said.
No Indian militant group has demonstrated the prowess of the gunmen who fended off commandos for several days in Mumbai, said Bruce Riedel, a former South Asia intelligence analyst at the CIA and the National Security Council.
"This is much more like the capabilities we've seen by [Lashkar-e-Taiba] and other Pakistan Kashmiri groups that have very close, long-standing links to Al Qaeda and who have been working together for a decade," Riedel said. "It is a dramatic demonstration that the global jihadist syndicate based in Pakistan is still as deadly as ever."
Western and Indian intelligence officials have charged that rogue elements in Pakistani intelligence agencies have long used Lashkar-e-Taiba and other Kashmiri militant groups as proxies in their confrontation with rival India.
Experts cautioned that it is far too early to tell whether that is true in the case of the Mumbai attacks. Some discounted it, saying the new civilian government in Pakistan wants and needs to forge closer ties to India and the United States, and has purged and reined in the security forces as a result.
Zardari said Saturday that there was at least a philosophical kinship between the Mumbai attackers and Islamic militants waging a violent campaign against his government.