"Al Qaeda has infected other groups in South Asia with its ideas. Pakistani Taliban sent, as you know, a bomber to Times Square (in New York). Lashkar-e-Taiba is acting in a more al-Qaeda-like manner," Peter Bergen, the Counter-terrorism Strategy Initiative Co-Director at New America Foundation, said.
He stated this during his testimony before the House Homeland and Security Committee, which organised a hearing on the evolving nature of terrorism, nine years after 9/11.
Of all the major terrorists groups in the region, Bergen said, LeT poses the highest threat to the US.
"Lashkar-e-Taiba, I think, is really probably the more important of all of these because it's the largest group. It attracts educated people," he said in response to a question.
"You know, the attack in Mumbai demonstrated that they were willing to hunt down Americans and Jews in the Nariman House and that they've adopted al Qaeda's ideology. And so I think that is quite worrisome," he said.
"The Pakistani Taliban, a real canary in the mine, which people didn't look at, was the fact that the Pakistani Taliban sent suicide bombers to Barcelona in January of '08, which should have demonstrated that these guys were willing to do attacks on the West. And Spanish prosecutors say the Pakistani Taliban were behind it," he said.
The Pakistani Taliban had admitted their role, he said, adding that luckily, the attack did not succeed.
"So Times Square was not an aberration. It was part of a pattern. So, you know, I think the Times Square incident speaks for itself," he said.
On the Haqqani network, Bergen said it seems to be very focussed on Afghanistan. They do not seem to be interested in out-of-area operations, he added.
Though the focus of late has been on Yemen in view of the botched Christmas Day bombing of a US airliner, Bergen said, he believes the al-Qaeda central is still on the Afghan-Pakistan border.
"This is where the ideology is and training continues," he said. "The drones have taken some impact on them, but I think to sort of say just because we've seen a lot of activity from al Qaeda in the Arabian Peninsula, as a story in The Washington Post said, that now that's the biggest problem, I just don't see that," he argued.
Bruce Hoffman, professor at the Georgetown University, said that al-Qaeda is "as opportunistic as it is instrumental, and where it sees the potential to spread and to expand, it takes advantage of those opportunities wherever they may appear."
"For them, I think the advantage is that it use to be that if terrorists wanted to join al Qaeda or an al Qaeda-like group, they had to go to either Afghanistan until 2000 or, in recent years, to Pakistan. Now they have closer options from the United States to travel to Somalia or to Yemen as well, perhaps other countries," he told the lawmakers.