oregon. a top counterterrorism official says the pace has been relentless. i can tell you that the past 13 months have been as intense, if not more intense, because of the variety of threats than any time since 2001. reporter: and no one sees the tempo slowing. we have seen all of these various threat streams kind of coming together and kind of hitting a confluence at the end of december here. so i thank you trend is going to continue into 2011. reporter: al qaeda central remains a threat. so is the pakistani taliban, which launched the attempted times square bombing. and al qaeda in the arabian peninsula, they dispatched the christmas day bomber and the toner cart train cargo bombs. in the past two year, nearly 50 american citizens have been charged with serious terrorism offenses and experts say home-grown radicalization will continue to be nurtured by the internet, including the online preachings of u.s.-born cleric,