From the shootings at Fort Hood to the civil war battlegrounds of Somalia, 2009 revealed more jihadist activities involving Americans than almost any year since the 9/11 attacks, say experts.
With the ongoing conflicts in Afghanistan and Iraq fueling anger among some Muslim Americans, experts say jihadist propaganda is gaining a foothold in the United States, with hundreds of English-language Web sites.
Many experts have long theorized that American Muslims tend to be better assimilated than Muslim immigrants in Europe and therefore less vulnerable to radicalization, but the number of recent homegrown terror incidents is raising concern.
Brian Jenkins, a terrorism expert at the Rand Corporation said there has been a "significant increase" in incidents over previous years.
"Our greatest concern is that individuals will become radicalized here, will go abroad, will be able to make contact with some terrorist organization, which will then provide them with the training and assistance to come back here to carry out a far more effect terrorist plots than those we have seen so far," Jenkins said.
A countermovement to combat Islamic radicalism has sprung up in an unlikely, but symbolic place.
Steps from where the 9/11 attacks occurred, in a building formerly housing a Burlington Coat Factory, a Muslim cultural center is planned. Imam Feisel, the cleric leading the project, and his wife, Daisy Khan, said they believe the center is a way to strengthen interfaith ties and educate the surrounding community about the true teachings of Islam.
"9/11 was a major attack, not only on America, but on our community as well," Khan said. "The side of Islam that Americans get to see is what's in the news -- mayhem, death, and destruction. We want to reverse that..."
On one of the coldest days of the year, about 200 Muslims attended a Friday service in an unheated room in the ground floor of the building, which is serving as a sort of makeshift mosque until the center is built.
The sermon was delivered in English and condemned those who "prostitute religion to fulfill their own agendas."
Those in attendance came from all walks of life, although they were almost all men. Many of the attendees worked in the area and were spending their lunch breaks to attend the service.
Sammy El-Gamal, who works for Soho Properties, the real estate investment firm that acquired the building, said he believes one of the missions of the cultural center will be to combat the negative images of Islam that have emerged since 9/11.
"I think we want to make the center a model of how people should act as Muslims," he said. "I think it will educate other people who have negative feelings about the religion and we should lead by example."
El-Gamal and other Muslims interviewed by ABC News at the center said they feel the recent incidents involving American Muslims engaged in jihad are not representative of the general U.S. Muslim population, which numbers about 3 million.
Terrorism expert Jenkins said the incidents represent "individual responses to what is happening in the Middle East and to the propaganda."
"The paucity of serious plots in this country and the very small numbers of individuals who have responded to this jihadist propaganda suggests to me that the American Muslim community is completely unsympathetic and indeed hostile to the jihadist enterprise," he added.
However, one need only look at Ground Zero to remember it only takes a few.