Indicative of the growing clout of the Lashkar-e-Taiba (LeT) despite an apparent crackdown by the Pakistani authorities, US security experts believe that the terror group and not Al-Qaeda has emerged as the main threat and could well stage the next major attack on the American mainland.
"We are and should be concerned about the threat LeT poses, given its global network," Juan Zarate, deputy national security adviser for counter-terrorism in the Bush administration, told the Chicago Tribune in an interview published on Sunday.
According to Zarate, the FBI and other US intelligence agencies had been focussing on the LeT as the next big threat to US security even before the Nov 26-29, 2008, Mumbai terror attacks.
The Tribune quoted US authorities as saying that the LeT was in many ways a bigger threat than the Al-Qaeda, whose leadership was on the run from numerous Predator strikes in the Pakistan's northwestern tribal areas.
Zarate's remarks come amidst reports that the LeT had got a new set of commanders to replace Zakiur Rehman Lakhvi and Zarrar Shah who the Pakistani authorities detained after the Mumbai carnage that India has blamed on the terror group.
Pakistani investigators initially pointed to an LeT hand in last week's attack on the Sri Lankan cricket team in Lahore but later ascribed it to the Al-Qaeda.
"We are and should be concerned about the threat LeT poses, given its global network," Zarate told the Tribune.
"It doesn't just reside in South Asia. It is an organisation that has potential reach all over the world, including the US," he added.
Bruce Riedel, chairman of the Obama administration's Pakistan-Afghanistan strategy review team, said he believed such a "global jihadist syndicate" of disaffected young Pakistanis was the most likely mechanism for launching an attack on US soil.
The Mumbai attacks, according to Riedel, was only the latest of several such by such militants on soft targets frequented by Americans, including hotels in Kabul and Islamabad.
The Mumbai mayhem had claimed the lives of over 170 people, including 26 foreigners - six of them American citizen. India had subsequently given the FBI access to Ajmal Amir Kasab, the sole terrorist captured alive during the carnage.
India says Kasab and nine other LeT operatives, all of whom were killed during the attacks that lasted for over 60 hours, had staged the assault.
India had also asked the FBI to examine evidence collected from five GPS phones used for coordinating the attack, requesting the FBI to analyse the data. The FBI established that the attack was mounted from the sea.
The Tribune said that Washington wanted Pakistan to not only dismantle LeT but also other similar groups founded during the Afghan war or later to participate in the insurgency in Jammu and Kashmir.
Quoting US and allied intelligence sources, the report claimed that potentially tens of thousands of Pakistanis had been trained in the LeT's guerrilla camps in Pakistan, many of whom had gone on to fight for the Al-Qaeda.
This includes a small number of US residents, some of who are believed to have returned home. Nearly a dozen Americans, including many members of the so-called Virginia Jihad Network, have been convicted in US courts of training at LeT camps and conspiring to provide material support to the group.
The US is also concerned about the thousands of disaffected Westerners and Pakistanis in Britain and other countries in Europe who travel frequently to Pakistan, the newspaper said.
Citizens of these countries do not need a visa for coming to the US.
An unknown number of those have trained in LeT camps, and after getting "indoctrinated in its hatred of the West and returning home, they were free to travel to the United States with virtually no background check", the Tribune said.