"I have home-grown violent extremist investigations in every single state," Comey told a meeting of state attorneys general. "Until a few weeks ago, there was (sic) 49 states. Alaska had none, which I couldn't quite figure out, but Alaska has now joined the group. So we have investigations of people in various stages of radicalizing in all 50 states."
Comey said the terror threat has "metastasized" in recent years, as the "progeny of Al Qaida take root" in safe havens such as Syria, Iraq, and Libya, using the Internet and social media to spread their propaganda and recruitment "at the speed of light."
"So why do I tell you this?" Comey asked. "To explain to you why this remains at the top of the FBI's list, and to explain to you why the conversations I have with our state and local partners in all 50 states matters so much today.
"Because ISIL in particular is putting out a siren song through their slick propaganda, through social media, that goes like this: 'Troubled soul, come to the Caliphate; you will live a life of glory; these are the apocalyptic end times; you will find a life of meaning here fighting for our so-called Caliphate. And if you can't come, kill somebody where you are.'"
Comey said terror attacks no longer have to be large-scale to advance the terrorists' mission. While Osama bin Laden's followers flew planes into buildings, today's terror groups advocate the killing of small groups and individuals: And if (they) can capture it on video and if it's somebody in uniform, all the better, because it will advance (their) mission."
Comey also said it's "highly unlikely" that a federal agent will be the first to hear about suspicious behavior: "It's going to be a deputy sheriff," he said. "It's going to be a police officer who knows that neighborhood."
Comey emphasized the importance of joint terrorism task forces that have been set up all around the country to counter the emerging "lone wolf" or returning-foreign-fighter threat.
"So all of us leaning forward to push information to each other and to make sure that if we see something, it quickly gets to the right place, is critical to responding to this threat."
On Wednesday, a joint terrorism task force in New York announced the arrests of three men from Brooklyn, two of whom were planning to join Islamic State fighters in Syria.
One of the suspects, 19-year-old Akhror Saidakhmetov of Kazakhstan, was arrested at Kennedy Airport, where he was trying to board a flight to Istanbul, with plans to head to Syria, authorities said.
Another man, 24-year-old Abdurasul Hasanovich Juraboev of Uzbekistan, had a ticket to travel to Istanbul next month and was arrested in Brooklyn, federal prosecutors said. Both men were in the country legally.
A third defendant, 30-year-old Abror Habibov of Uzbekistan, is accused of helping to fund Saidakhmetov's travel plans. Habibov was in the U.S. on an expired visa.
Earlier this week, two immigrants with ties to Southern California were sentenced to 25 years in prison for plotting to murder U.S. troops in Afghanistan and for providing material support to al Qaeda.
As CNSNews.com reported, one of the men was a naturalized U.S. citizen who came here from Afghanistan (and later returned). The other was a legal permanent resident from the Philippines.
2 Immigrants Who Plotted to Kill Americans Get 25 Years in Prison