Plots by American-based Islamic terrorists with no direct ties to international terror networks form a large and growing threat to America, according to FBI and other security officials.
"The trend we're seeing is that we are uncovering more instances of people here who have been radicalised ... where there is not a direct thumbprint of Al Qaeda," John Miller, the FBI's assistant director for public affairs, was cited as saying by "USA Today".
Justice Department records show that the FBI and other federal and local agencies have led prosecutions of a dozen such alleged plots since the Sep 11 attacks on New York City and Washington, the daily said on Monday.
The latest began last Tuesday, when five New Jersey Muslim men were charged with plotting to kill soldiers at the Army's Fort Dix, NJ, compound. A sixth man was charged with helping the group obtain illegal firearms. The government has won terrorism convictions in seven cases. Others are ongoing.
The focus on American-based terror cells is a shift from post 9/11 thinking, when intelligence and security officials expected attacks to come from "sleeper cells" of Al Qaeda agents who, like the Washington and New York City attackers, had filtered into the USA from abroad.
"That was my intuition at the time," George Tenet, CIA director from 1997 to 2004, told the daily. Tenet has just released a book, At the Centre of the Storm, about his tenure. Tenet says the lesson is "don't get fixed on a particular face (because) there may be multiple kinds of faces."
USA Today quoted Pasquale D'Amuro, the FBI's counter-terrorism chief in 2002 and 2003, as saying the alleged New Jersey plot appears to be such a case. The six men arrested, he notes, were born in the former Yugoslavia, Jordan and Turkey and had lived in the USA without incident. One was a citizen, two were legal residents and three were here illegally. They had lived here at least six years, neighbours said.
"If they look like the neighbours next door, it's because that's what they are," says D'Amuro, CEO of Giuliani Security and Safety in New York.
"That they would come here, be welcomed and then want to attack us - that's what people have a hard time understanding."
In some cases, such as that of six Yemeni-Americans in Lackawanna, New York, the accused plotters had undergone training at terrorist camps overseas but had not focused on an American target.
In others, such as the New Jersey plot, the government alleges that plotters had identified targets and were trying to purchase arms.
In six cases, accused plotters sought out undercover agents or informers posing as Al Qaeda representatives. In two cases, alleged plotters are accused of swearing allegiance to Al Qaeda in ceremonies staged by the phony Islamists. In eight cases, the accused plotters were native-born Americans, including about a dozen who were converts to Islam.
Intelligence analysts cited by USA Today say the lack of an Al Qaeda-led terror strike here may signal that the group is waiting until it can mount an attack that will equal the 9/11 strikes in casualties and publicity value.