“It makes it sound like it couldn’t happen here because we are the good immigrants: hard-working, close-knit, educated,” said Junaid Rana, an assistant professor of Asian-American studies at the University of Illinois at Urbana-Champaign and an American-born son of Pakistani immigrants. “But we are talking about a cult mind-set, how a cult does its brainwashing.”

Image Businesses on Devon Avenue in Chicago, like an Islamic bookstore, attract a large Pakistani clientele. Credit... Kenneth Dickerman for The New York Times

Yet one major difference between the United States and Britain, some say, is the United States’ historical ideal of being a melting-pot meritocracy.

“You can keep the flavor of your ethnicity, but you are expected to become an American,” said Omer Mozaffar, 34, a Pakistani-American raised here who is working toward a doctorate in Islamic studies at the University of Chicago.

Britain remains far more rigid. In the United States, for example, Pakistani physicians are more likely to lead departments at hospitals or universities than they are in Britain, said Dr. Tariq H. Butt, a 52-year-old family physician who arrived in the United States 25 years ago for his residency.

Nationwide, Pakistanis appear to be prospering. The census calculated that mean household income in the United States in 2002 was $57,852 annually, while that for Asian households, which includes Pakistanis, was $70,047. By contrast, about one-fifth of young British-born Muslims are jobless, and many subsist on welfare.

Hard numbers on how many people of Pakistani descent live in the United States do not exist, but a forthcoming book from Harvard University Press on charitable donations among Pakistani-Americans, “Portrait of a Giving Community,” puts the number around 500,000, with some 35 percent or more of them in the New York metropolitan area. Chicago has fewer than 100,000, while other significant clusters exist in California, Texas and Washington, D.C.

Pakistani immigration to the United States surged after laws in the 1960’s made it easier for Asians to enter the country. Most were drawn by jobs in academia, medicine and engineering. It was only in the late 1980’s and 90’s that Pakistanis arrived to work blue-collar jobs as taxi drivers or shopkeepers, said Adil Najam, the author of the book on donations and an international relations professor at the Fletcher School of Law and Diplomacy at Tufts University.