officials were quoted by the New York Times as saying that LeT has quietly gained strength in recent years with the assistance of Pakistan's Inter-Services Intelligence (ISI), which has allowed the group to train and raise money while other militants have been under siege.
Officials said though there is no hard evidence yet to link the spy agency to the Mumbai attacks, ISI shared intelligence with Lashkar and provided protection for it.
The ISI has shared intelligence with Lashkar and provided protection for it, the officials told the paper, and investigators are focusing on one Lashkar leader they believe is a main liaison with the spy service and a mastermind of the attacks.
"People are having to go back and relook at all the connections," one American counterterrorism official, who was among several officials who spoke on condition of anonymity to the paper, was quoted as saying.
American and Indian officials believe that one senior Lashkar commander in particular, Zarrar Shah, is one of the group's primary liaisons to the ISI. "He's a central character in this plot," one American official said.
As a result of the assault India's financial hub, American counterterrorism and military officials say they are reassessing their view of Lashkar and believe it to be more capable and a greater threat than they had previously recognized.
Pakistani officials have denied any government connection to the siege on November 26-29, in which nearly 200 people were killed in Mumbai.
As American, European and Middle Eastern governments crack down on al-Qaeda's finances, Lashkar still has a flourishing fund-raising organization in South Asia and the Persian Gulf region, including Saudi Arabia, the Times quoted counterterrorism officials as saying. The group primarily uses its charity wing, Jamaat-ud-Dawa, to raise money, ostensibly for causes in Pakistan.
Lashkar, the Times noted, also has a history of using local extremist groups for knowledge and tactics in its operations. Investigators in Mumbai are following leads suggesting that Lashkar used the Students' Islamic Movement of India, a fundamentalist group that advocates establishing an Islamic state in India, for early reconnaissance and logistical help.
Hoffman told the paper that Lashkar had developed particularly sophisticated Internet operations, and that intelligence officials believed the group had forged ties with regional terrorist organizations like Jemaah Islamiyah in Indonesia by assisting them with their own Internet strategies.
Pakistan is under intense international pressure, including from the US, to take action against the LeT for its involvement in the Mumbai attacks. The Let was founded by militant ideologue Hafiz Mohammad Saeed, who formed the Jamaat soon after the Lashker was banned in 2001.