A "clear, if carefully worded warning" has been delivered by US officials after it was discovered that Faisal Shahzad, the man behind the recent failed attack on Times Square was the son of a retired Pakistani air marshal.
The father is one of Pakistan's most accomplished pilots and flight instructors and was stationed overseas in Britain and Saudi Arabia.
"We've got elements of the Pakistani gentry - people who can get in and out of the United States with ease, if they're not already citizens here-who are getting roped into terrorism," a US official said.
It is understood the message was delivered last week when James Jones, the National Security Adviser, and Leon Panetta, the CIA director, met their counterparts in Pakistan.
The US has for years suspected that elements of the Pakistani military and intelligence service are connected to terror groups. It has publicly warned Pakistan of severe consequences if Pakistani terrorists attempt to strike America again.
The home-made car bomb which failed to detonate on May 1 at busiest time of day in New York's theatre district could have wreaked heavy damage.
Another confessed bomb plotter, David Headley, is the son of a retired senior Pakistani diplomat who may have served at the Pakistani embassy in Washington. His late mother was American but he changed his name to Daood Gilani to make crossing international borders easier. His half brother is spokesman for the prime minister of Pakistan.
Headley is facing a life sentence after admitting his involvement both in the 2008 terrorist attacks in downtown Mumbai and in a foiled plot to attack the Danish newspaper that stoked a global controversy by publishing cartoons of the Prophet Mohammed in 2005.
Teresita Schaffer, a retired American diplomat who worked in Pakistan, said the sons of the privileged had been involved in terror since the inception of al-Qaeda, whose leaders are from wealthy backgrounds.
"The thread running through this is that the leaders who build bombs and direct operations are not poor and down trodden. I don't think being child of privilege a military officer predisposes anyone to terrorism, but it certainly doesn't immunise.
US officials are investigating reports that a Pakistani army major was arrested this week in Pakistan on the suspicion of involvement in the Times Square plot.
Shahzad, who lost his job and then his house in the run up to the New York attack, is still talking to investigators and made his first court appearance this week. He has yet to enter a plea.
